GLASS

Abstract

A glass which satisfies formulas (1) and (2), where a liquid phase temperature is denoted by T.sub.L ( C.), a Young's modulus calculated based on the composition is denoted by E (GPa), and a linear thermal expansion coefficient is denoted by (ppm/ C.),

[00001]$\begin{array}{cc}13.1E+9-T_{L}0& \left(1\right)\end{array}$$\begin{array}{cc}1923-156-T_{L}0.& \left(2\right)\end{array}$

Claims

1. A glass, having a liquid phase temperature is denoted by T.sub.L (C), a Young's modulus is denoted by E (GPa), and a linear thermal expansion coefficient is denoted by (ppm/ C.), that satisfies formulas (1) and (2): $\begin{array}{cc}13.1E+9-T_{L}0& \left(1\right)\end{array}$ $\begin{array}{cc}1923-156-T_{L}0.& \left(2\right)\end{array}$

2. The glass according to claim 1, wherein the glass comprises, in terms of mol % on an oxide basis, SiO.sub.2: 40% to 65%, B.sub.2O3: 0.01% to 15%, Al.sub.2O.sub.3+a rare earth oxide: 0% to 20%, and Y.sub.2O.sub.3+Gd.sub.2O.sub.3+Ta.sub.2O.sub.5+La.sub.2O.sub.3+Nd.sub.2O.sub.3+Nb.sub.2O.sub.5: 0.5% or more.

3. The glass according to claim 2, wherein the glass comprises, in terms of mol % on an oxide basis, SiO.sub.2: 44% to 64%, B.sub.2O.sub.3: 1% to 13%, Al.sub.2O3: 5% to 20%, and Y.sub.2O.sub.3+Gd.sub.2O.sub.3+Ta.sub.2O.sub.5+La.sub.2O.sub.3+Nd.sub.2O.sub.3+Nb.sub.2O.sub.5: 1to 10%.

4. The glass according to claim 1, having a composition in terms of mol % on an oxide basis that satisfies: $0.1\left\{\left({\mathrm{Al}}_2{O}_3+\mathrm{MgO}\right)/\left({\mathrm{SiO}}_2+{\mathrm{Al}}_2{O}_3+B_2{O}_3+\mathrm{MgO}\right)\right\}1,$ $0.5\left(\mathrm{MgO}\right)/\left(.Math.RO\right)1,\mathrm{and}$ $0\%{\mathrm{Al}}_2{O}_3+\mathrm{rare}\mathrm{earth}\mathrm{oxides}20\%,$ where, RO refers to a total content of an alkaline earth metal oxide contained in the glass.

5. The glass according to claim 1, having a Young's modulus parameter Y calculated by Formula (3) of 0.8 or more, $\begin{array}{cc}Y=\left(123-0.54\left[{\mathrm{SiO}}_2\right]+0.3\left[{\mathrm{Al}}_2{O}_3\right]-1.15\left[B_2{O}_3\right]+0.21\left[\mathrm{MgO}\right]-0.2\left[\mathrm{CaO}\right]-0.1\left[\mathrm{SrO}\right]-1.2\left[\mathrm{BaO}\right]+\left[{\mathrm{Li}}_{2}O\right]-2.8\left[K_{2}O\right]+0.05\left[\mathrm{ZnO}\right]+1.46\left[{\mathrm{ZrO}}_2\right]-0.05\left[{\mathrm{TiO}}_2\right]+1.6\left[Y_2{O}_3\right]+1.35\left[{\mathrm{Gd}}_2{O}_3\right]+1.37\left[{\mathrm{La}}_2{O}_3\right]+\left[{\mathrm{Ta}}_2{O}_5\right]\right)/100;& \left(3\right)\end{array}$ a liquid phase parameter L calculated by Formula (4) of 10.5 or less, $\begin{array}{cc}L=\left(-642.5+20.6\left[{\mathrm{SiO}}_2\right]+31.9\left[{\mathrm{Al}}_2{O}_3\right]+2.85\left[B_2{O}_3\right]+11.24\left[\mathrm{MgO}\right]+17.3\left[\mathrm{CaO}\right]+1.7\left[\mathrm{SrO}\right]+31.4\left[\mathrm{BaO}\right]-6.86\left[{\mathrm{Li}}_{2}O\right]+38\left[K_{2}O\right]+11.5\left[\mathrm{ZnO}\right]+25.8\left[{\mathrm{ZrO}}_2\right]+41\left[{\mathrm{TiO}}_2\right]+12.3\left[Y_2{O}_3\right]-1.2\left[{\mathrm{Gd}}_2{O}_3\right]-1.2\left[{\mathrm{La}}_2{O}_3\right]+24.5\left[{\mathrm{Ta}}_2{O}_5\right]\right)/125;\mathrm{and}& \left(4\right)\end{array}$ a thermal expansion parameter C calculated by Formula (5) of 0.9 or less, $\begin{array}{cc}C=\left(14.098-0.1245\left[{\mathrm{SiO}}_2\right]-0.131\left[{\mathrm{Al}}_2{O}_3\right]-0.101\left[B_2{O}_3\right]-0.051\left[\mathrm{MgO}\right]+0.013\left[\mathrm{CaO}\right]+0.053\left[\mathrm{SrO}\right]+0.018\left[\mathrm{BaO}\right]+0.041\left[{\mathrm{Li}}_{2}O\right]+0.395\left[{\mathrm{Na}}_{2}O\right]-0.066\left[\mathrm{ZnO}\right]-0.033\left[{\mathrm{ZrO}}_2\right]-0.072\left[{\mathrm{TiO}}_2\right]+0.035\left[Y_2{O}_3\right]+0.074\left[{\mathrm{Gd}}_2{O}_3\right]+0.074\left[{\mathrm{La}}_2{O}_3\right]-0.091\left[{\mathrm{Ta}}_2{O}_5\right]\right)/5\underset{\_}{,}& \left(5\right)\end{array}$ where in formulas (3)-(5), [R.sub.xO.sub.y] represents a content of an oxide R.sub.xO.sub.y contained in the glass measured in mol % on an oxide basis.

6. The glass according to claim 1, wherein the glass is a substrate.

7. The glass according to claim 6, wherein the glass is used for manufacturing at least one of a fan out wafer level package or a fan out panel level package.

8. A semiconductor support device, comprising a substrate comprising the glass of claim 1; and a semiconductor chip disposed on a surface of the glass.

9. A method of forming a semiconductor package, the method comprising attaching a semiconductor chip to a surface of a first glass to form a first supported chip; covering the semiconductor chip and the surface of the first glass with an encapsulating material to form an element substrate; separating the encapsulating material and semiconductor chip from the first glass to form a second supported chip; bonding a second glass to a surface of the second supported chip opposite to a surface in contact with the semiconductor chip to form a third supported chip; forming on a surface of the semiconductor chip at least one selected from the group consisting of wiring and soldering bumps; and separating the encapsulating material and semiconductor chip from the second glass to form a second supported chip to form the semiconductor package, wherein at least one selected from the group consisting of the first glass and the second glass is the glass of claim 1.

10. The method of claim 9, wherein the semiconductor package is at least one selected from the group consisting of a fan out wafer level package and a fan out panel level package.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a schematic diagram of a glass according to the present embodiment.

[0009] FIG. 2 is a schematic diagram for explaining deflection evaluation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, suitable embodiments of the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to the embodiments, and in a case where a plurality of embodiments is provided, the present invention includes a combination of the embodiments. The numerical value includes a range of rounding. The numerical range represented by to means a numerical range including numerical values before and after to as a lower limit value and an upper limit value, and in a case where to is used in the following description, the same meaning is given.

Glass

[0011] FIG. 1 is a schematic diagram of a glass according to the present embodiment. As illustrated in FIG. 1, a glass 10 according to the present embodiment is used as a glass substrate for manufacturing a semiconductor package, and more specifically, is a supporting glass substrate for manufacturing FOWLP or the like. However, the use of the glass 10 is not limited to the manufacturing FOWLP or the like, and may be optional, and the glass 10 may be a glass substrate used for supporting a member or may be used for purposes other than supporting the member. FOWLP or the like include a fan out wafer level package (FOWLP) and a fan out panel level package (FOPLP).

Liquid Phase Temperature

[0012] The liquid phase temperature of the glass 10 is denoted by T.sub.L ( C.), the Young's modulus of the glass 10 is denoted by E (GPa), and the linear thermal expansion coefficient of the glass 10 is denoted by (ppm/ C.). In this case, the liquid phase temperature T.sub.L of the glass 10 preferably satisfies the following Formulae (1) and (2). When Formulae (1) and (2) are satisfied, the liquid phase temperature can be kept relatively low, and the manufacturing can be facilitated while deflection is minimized.

[00003]$\begin{array}{cc}13.1E+9-T_{L}0& \left(1\right)\end{array}$$\begin{array}{cc}1923-156-T_{L}0& \left(2\right)\end{array}$

[0013] The liquid phase temperature T.sub.L can be evaluated by placing glass particles that pass through a sieve with a mesh width of 4.0 mm and do not pass through a sieve with a mesh width of 2.3 mm on a platinum dish, and then holding the glass particles in an electric furnace set at a predetermined temperature for one hour to measure the temperature at which crystals are precipitated.

[0014] The left side (13.1E+9T.sub.L) of Formula (1) is preferably 17 or more, more preferably 33 or more, more preferably 42 or more, more preferably 63 or more, more preferably 92 or more, and still more preferably 117 or more.

[0015] The left side (1923156T.sub.L) of Formula (2) is preferably 12 or more, more preferably 22 or more, more preferably 42 or more, more preferably 62 or more, more preferably 72 or more, and still more preferably 102 or more.

[0016] The Young's modulus E can be measured by an ultrasonic pulse method defined in JIS R 1602:1995 Testing methods for elastic modulus of fine ceramics. The bulk density of a sample can be measured by the Archimedes method, and the longitudinal wave velocity and the transverse wave velocity are measured using an ultrasonic thickness meter 38DL PLUS manufactured by Olympus Corporation to determine a value of the Young's modulus.

[0017] On the other hand, the linear thermal expansion coefficient is an average thermal expansion coefficient within a range of 50 C. to 200 C., and is a value measured in accordance with DIN-51045-1 as a standard for thermal expansion measurement. For example, the measurement may be performed within a range of 30 C. to 300 C. using a thermal expansion meter (DIL 402 Expedis Supreme) manufactured by NETZSCH Group as a measuring apparatus, and an average thermal expansion coefficient within a range of 50 C. to 200 C. in that measurement range may be used as the linear thermal expansion coefficient.

[0018] The liquid phase temperature T.sub.L of the glass 10 is preferably 1300 C. or lower, more preferably 800 C. or higher and 1290 C. or lower, more preferably 825 C. or higher and 1280 C. or lower, more preferably 850 C. or higher and 1270 C. or lower, more preferably 875 C. or higher and 1260 C. or lower, more preferably 900 C. or higher and 1250 C. or lower, more preferably 925 C. or higher and 1240 C. or lower, more preferably 950 C. or higher and 1230 C. or lower, more preferably 975 C. or higher and 1220 C. or lower, more preferably 1000 C. or higher and 1210 C. or lower, and still more preferably 1200 C. or lower. By setting the liquid phase temperature within this range, the manufacturing can be facilitated.

Young's Modulus

[0019] The Young's modulus E of the glass 10 is preferably 80 GPa or more, more preferably 85 GPa or more and 180 GPa or less, more preferably 88 GPa or more and 170 GPa or less, more preferably 90 GPa or more and 160 GPa or less, more preferably 93 GPa or more and 150 GPa or less, more preferably 95 GPa or more and 145 GPa or less, more preferably 97 GPa or more and 140 GPa or less, more preferably 98 GPa or more and 135 GPa or less, still more preferably 99 GPa or more and 130 GPa or less. By setting the Young's modulus within this range, deflection can be appropriately minimized, and cutting, grinding, and polishing processing can be facilitated.

Linear Thermal Expansion Coefficient

[0020] The linear thermal expansion coefficient of the glass 10 is preferably 4.5 ppm/ C. or less, more preferably 2.0 ppm/ C. or more and 4.3 ppm/ C. or less, more preferably 2.1 ppm/ C. or more and 4.1 ppm/ C. or less, more preferably 2.2 ppm/ C. or more and 4 ppm/ C. or less, more preferably 2.3 ppm/ C. or more and 3.9 ppm/ C. or less, more preferably 2.4 ppm/ C. or more and 3.8 ppm/ C. or less, more preferably 2.5 ppm/ C. or more and 3.75 ppm/ C. or less, more preferably 2.6 ppm/ C. or more and 3.7 ppm/ C. or less, more preferably 2.7 ppm/ C. or more and 3.65 ppm/ C. or less, and still more preferably 2.8 ppm/ C. or more and 3.6 ppm/ C. or less. By setting the linear thermal expansion coefficient within this range, deflection can be appropriately minimized.

[0021] The linear thermal expansion coefficient of the glass 10 may be within the following range. The linear thermal expansion coefficient of the glass 10 is preferably 5.0 ppm/ C. or less, more preferably 3.6 ppm/ C. or more and 4.9 ppm/ C. or less, more preferably 3.7 ppm/ C. or more and 4.8 ppm/ C. or less, more preferably 3.8 ppm/ C. or more and 4.7 ppm/ C. or less, more preferably 3.85 ppm/ C. or more and 4.65 ppm/ C. or less, more preferably 3.9 ppm/ C. or more and 4.6 ppm/ C. or less, more preferably 3.95 ppm/ C. or more and 4.55 ppm/ C. or less, more preferably 4 ppm/ C. or more and 4.5 ppm/ C. or less, more preferably 4.1 ppm/ C. or more and 4.45 ppm/ C. or less, and still more preferably 4.2 ppm/ C. or more and 4.4 ppm/ C. or less. By setting the linear thermal expansion coefficient within this range, deflection can be appropriately minimized.

Young's Modulus Parameter

[0022] A Young's modulus parameter Y of the glass 10 calculated from a composition is preferably 0.8 or more, more preferably 0.85 or more and 1.8 or less, more preferably 0.88 or more and 1.7 or less, more preferably 0.9 or more and 1.6 or less, more preferably 0.93 or more and 1.5 or less, more preferably 0.95 or more and 1.45 or less, more preferably 0.97 or more and 1.4 or less, more preferably 0.98 or more and 1.35 or less, and still more preferably 0.99 or more and 1.3 or less. By setting the Young's modulus parameter within this range, deflection can be appropriately minimized.

[0023] The Young's modulus parameter Y is calculated from the following Formula (3).

[00004]$\begin{array}{cc}Y=\left(123-0.54\left[{\mathrm{SiO}}_2\right]+0.3\left[{\mathrm{Al}}_2{O}_3\right]-1.15\left[B_2{O}_3\right]+0.21\left[\mathrm{MgO}\right]-0.2\left[\mathrm{CaO}\right]-0.1\left[\mathrm{SrO}\right]-1.2\left[\mathrm{BaO}\right]+\left[{\mathrm{Li}}_{2}O\right]-2.8\left[K_{2}O\right]+0.05\left[\mathrm{ZnO}\right]+1.46\left[{\mathrm{ZrO}}_2\right]-0.05\left[{\mathrm{TiO}}_2\right]+1.6\left[Y_2{O}_3\right]+1.35\left[{\mathrm{Gd}}_2{O}_3\right]+1.37\left[{\mathrm{La}}_2{O}_3\right]+\left[{\mathrm{Ta}}_2{O}_5\right]\right)/100& \left(3\right)\end{array}$

[0024] The content of the oxide R.sub.xO.sub.y (R is an element constituting an oxide, and x and y are any integers) contained in the glass 10 is represented by [R.sub.xO.sub.y] in terms of mol % on an oxide basis. The content herein refers to the ratio of the content of the oxide R.sub.xO.sub.y to the total glass 10 in terms of mol % on an oxide basis. That is, for example, [SiO.sub.2] in Formula (3) refers to the ratio of the content of SiO.sub.2 to the total glass 10 in terms of mol % on an oxide basis.

[0025] In addition, the glass 10 may not contain all the oxides represented in Formula (3). In Formula (3), the content of the oxides not contained in the glass 10 is considered to be zero. In addition, the glass 10 may contain components other than the oxides represented in Formula (3).

Liquid Phase Parameter

[0026] A liquid phase parameter L of the glass 10 calculated from the composition is preferably 10.5 or less, more preferably 6.4 or more and 10.4 or less, more preferably 7.2 or more and 10.3 or less, more preferably 7.6 or more and 10.2 or less, more preferably 7.7 or more and 10.1 or less, more preferably 7.8 or more and 10 or less, more preferably 7.9 or more and 9.9 or less, and still more preferably 8 or more and 9.8 or less. By setting the liquid phase parameter L within this range, the liquid phase temperature can be kept low, and the manufacturing can be facilitated.

[0027] The liquid phase parameter L is calculated from the following Formula (4).

[00005]$\begin{array}{cc}L=\left(-642.5+20.6\left[{\mathrm{SiO}}_2\right]+31.9\left[{\mathrm{Al}}_2{O}_3\right]+2.85\left[B_2{O}_3\right]+11.24\left[\mathrm{MgO}\right]+17.3\left[\mathrm{CaO}\right]+1.7\left[\mathrm{SrO}\right]+31.4\left[\mathrm{BaO}\right]-6.86\left[{\mathrm{Li}}_{2}O\right]+38\left[K_{2}O\right]+11.5\left[\mathrm{ZnO}\right]+25.8\left[{\mathrm{ZrO}}_2\right]+41\left[{\mathrm{TiO}}_2\right]+12.3\left[Y_2{O}_3\right]-1.2\left[{\mathrm{Gd}}_2{O}_3\right]-1.2\left[{\mathrm{La}}_2{O}_3\right]+24.5\left[{\mathrm{Ta}}_2{O}_5\right]\right)/125& \left(4\right)\end{array}$

[0028] The glass 10 may not contain all the oxides represented in Formula (4). In Formula (4), the content of the oxide not contained in the glass 10 is considered to be zero. In addition, the glass 10 may contain components other than the oxides represented in Formula (4).

Thermal Expansion parameter

[0029] A thermal expansion parameter C of the glass 10 calculated from the composition is preferably 0.9 or less, more preferably 0.4 or more and 0.86 or less, more preferably 0.42 or more and 0.82 or less, more preferably 0.44 or more and 0.8 or less, more preferably 0.46 or more and 0.79 or less, more preferably 0.48 or more and 0.78 or less, more preferably 0.5 or more and 0.77 or less, more preferably 0.52 or more and 0.76 or less, more preferably 0.54 or more and 0.75 or less, and still more preferably 0.56 or more and 0.74 or less. By setting the thermal expansion parameter C within this range, the linear thermal expansion coefficient can be kept low, and deflection can be appropriately minimized.

[0030] In addition, the thermal expansion parameter C of the glass 10 may be within the following range. The thermal expansion parameter C of the glass 10 is preferably 1.0 or less, more preferably 0.72 or more and 0.98 or less, more preferably 0.74 or more and 0.96 or less, more preferably 0.76 or more and 0.94 or less, more preferably 0.77 or more and 0.93 or less, more preferably 0.78 or more and 0.92 or less, more preferably 0.79 or more and 0.91 or less, more preferably 0.8 or more and 0.9 or less, more preferably 0.82 or more and 0.89 or less, and still more preferably 0.84 or more and 0.88 or less.

[0031] The thermal expansion parameter C is calculated from the following Formula (5).

[00006]$\begin{array}{cc}C=\left(14.098-0.1245\left[{\mathrm{SiO}}_2\right]-0.131\left[{\mathrm{Al}}_2{O}_3\right]-0.101\left[B_2{O}_3\right]-0.051\left[\mathrm{MgO}\right]+0.013\left[\mathrm{CaO}\right]+0.053\left[\mathrm{SrO}\right]+0.018\left[\mathrm{BaO}\right]+0.041\left[{\mathrm{Li}}_{2}O\right]+0.395\left[{\mathrm{Na}}_{2}O\right]-0.066\left[\mathrm{ZnO}\right]-0.033\left[{\mathrm{ZrO}}_2\right]-0.072\left[{\mathrm{TiO}}_2\right]+0.035\left[Y_2{O}_3\right]+0.074\left[{\mathrm{Gd}}_2{O}_3\right]+0.074\left[{\mathrm{La}}_2{O}_3\right]-0.091\left[{\mathrm{Ta}}_2{O}_5\right]\right)/5& \left(5\right)\end{array}$

[0032] The glass 10 may not contain all the oxides represented in Formula (5). In Formula (5), the content of the oxide not contained in the glass 10 is considered to be zero, and the same applies hereafter. In addition, the glass 10 may contain components other than the oxides represented in Formula (5).

Composition of Glass

[0033] Next, a preferred composition of the glass 10 will be described. However, the glass 10 may have any composition in which the liquid phase temperature T.sub.L satisfies the above-described range.

SiO.SUB.2

[0034] The glass 10 preferably contains SiO.sub.2 (the content of SiO.sub.2 is higher than 0 mol %). SiO.sub.2 is a component for reducing the linear thermal expansion coefficient and is a component for controlling the magnitude of the Young's modulus. In addition, in order to appropriately control an increase in the melting temperature and the liquid phase temperature, the content of SiO.sub.2 is preferably 65% or less. In the glass 10, the content of SiO.sub.2 is preferably 40% or more and 65% or less, preferably 44% or more and 64% or less, preferably 44% or more and 62% or less, preferably 46% or more and 60% or less, preferably 49% or more and 58% or less, preferably 50% or more and 57% or less, preferably 51% or more and 56% or less, preferably 52% or more and 55% or less, and more preferably 52.5% or more and 54% or less in terms of mol % on an oxide basis. When the content of SiO.sub.2 is within this range, the manufacturing can be facilitated while deflection is minimized.

Al.SUB.2.O.SUB.3.+Rare Earth Oxide

[0035] The glass 10 preferably contains at least one of Al.sub.2O.sub.3 or a rare earth oxide. The rare earth oxide herein may be one kind of rare earth oxide or a plurality of kinds of rare earth oxides. When Al.sub.2O.sub.3 and the rare earth oxide are contained, the Young's modulus is increased. In the glass 10, the total content (Al.sub.2O.sub.3+rare earth oxide) of Al.sub.2O.sub.3 and the rare earth oxide is preferably 0% or more and 20% or less, more preferably 5% or more and 18% or less, more preferably 9% or more and 17.5% or less, more preferably 10% or more and 17% or less, more preferably 10.5% or more and 16.5% or less, more preferably 11% or more and 16% or less, more preferably 11.5% or more and 15.5% or less, and more preferably 12% or more and 15% or less in terms of mol % on an oxide basis. When the total content of Al.sub.2O.sub.3 and the rare earth oxide is within this range, the liquid phase temperature can be lowered to facilitate the manufacturing.

[0036] The total content of Al.sub.2O.sub.3 and the rare earth oxide refers to the ratio of the total value of the content of Al.sub.2O.sub.3 and the content of the rare earth oxide to the total glass 10. In addition, the glass 10 is not limited to containing both Al.sub.2O.sub.3 and the rare earth oxide. The total content of Al.sub.2O.sub.3 and the rare earth oxide refers to, for example, the content of Al.sub.2O.sub.3 in a case where the rare earth oxide is not contained, and refers to the content of the rare earth oxide in a case where Al.sub.2O.sub.3 is not contained. When a plural of kinds of rare earth oxides is contained, the content of the rare earth oxides refers to the total content of these rare earth oxides.

[0037] Al.sub.2O.sub.3

[0038] Al.sub.2O.sub.3 has effects of increasing the Young's modulus to minimize deflection and inhibit phase separation of glass, but when the content of Al.sub.2O.sub.3 is less than 5%, these effects are less likely to be exhibited. In addition, by setting the content of Al.sub.2O.sub.3 to 20% or less, an increase in the liquid phase temperature can be controlled. Therefore, in the glass 10, the content of Al.sub.2O.sub.3 is preferably 5% or more and 20% or less, more preferably 78 or more and 19% or less, more preferably 8% or more and 18.5% or less, more preferably 9% or more and 18% or less, more preferably 9.5% or more and 17.5% or less, more preferably 10% or more and 17% or less, more preferably 10.5% or more and 16.5% or less, more preferably 11% or more and 16% or less, more preferably 11.5% or more and 15.5% or less, and more preferably 12% or more and 15% or less in terms of mol % on an oxide basis. When the content of Al.sub.2O.sub.3 is within this range, the manufacturing can be facilitated while deflection is minimized.

[0039] B.sub.2O.sub.3

[0040] B.sub.2O.sub.3 has effects of reducing devitrification caused by crystallization of glass to facilitate the manufacturing, and controlling Young's modulus. Therefore, the glass 10 may not contain B.sub.2O.sub.3 (the content of B.sub.2O.sub.3 is 0 mol %), but may contain B.sub.2O.sub.3. The content of B.sub.2O.sub.3 is preferably 0.01% or more and 15% or less, preferably 18 or more and 13% or less, preferably 3% or more and 12% or less, preferably 5% or more and 11% or less, preferably 6% or more and 10% or less, preferably 6.5% or more and 9.5% or less, and more preferably 7% or more and 9% or less in terms of mol % on an oxide basis. When the content of B.sub.2O.sub.3 is within this range, the manufacturing can be facilitated while deflection is minimized.

MgO

[0041] Since MgO increases the Young's modulus without increasing the density, the deflection can be minimized by increasing the specific elastic modulus. In addition, there is also an effect of reducing the linear thermal expansion coefficient. By setting the content of MgO to 30% or less, the liquid phase temperature can be controlled to be low. Therefore, the glass 10 may not contain MgO (the content of MgO is 0 mol %), but may contain MgO. In the glass 10, the content of MgO is preferably 1% or more and 30% or less, more preferably 5% or more and 29.5% or less, more preferably 9% or more and 29% or less, more preferably 10% or more and 28.5% or less, more preferably 11% or more and 28% or less, more preferably 12% or more and 27.5% or less, more preferably 13% or more and 27% or less, more preferably 14% or more and 26.5% or less, more preferably 15% or more and 26% or less, more preferably 16% or more and 25.5% or less, more preferably 17% or more and 25% or less, more preferably 18% or more and 24.5% or less, more preferably 19% or more and 24% or less, more preferably 19.5% or more and 23.5% or less, and more preferably 20% or more and 23% or less in terms of mol % on an oxide basis. When the content of MgO is within this range, the manufacturing can be facilitated while deflection is minimized.

CaO

[0042] CaO has a characteristic of increasing the specific elastic modulus next to MgO among the oxides of Group 2 elements and not excessively reducing the linear thermal expansion coefficient, and further has a characteristic less likely to increase the liquid phase temperature as compared with MgO. Therefore, the glass 10 may not contain CaO (the content of CaO is 0 mol %), but may contain CaO. By setting the content of CaO to 5% or less, an increase in the linear thermal expansion coefficient can be minimized, and the liquid phase temperature can be controlled to be low. In the glass 10, the content of Cao is preferably 0.01% or more and 5% or less, more preferably 0.1% or more and 3% or less, more preferably 0.15% or more and 2% or less, more preferably 0.2% or more and 1.3% or less, more preferably 0.25% or more and 1% or less, and more preferably 0.3% or more and 0.5% or less in terms of mol % on an oxide basis. When the content of CaO is within this range, the manufacturing can be facilitated while deflection is minimized.

SrO

[0043] SrO has an effect of improving the solubility of glass and reducing the liquid phase temperature. Therefore, the glass 10 may not contain SrO (the content of SrO is 0 mol %), but may contain SrO. By setting the content of SrO to 5% or less, an increase in the linear thermal expansion coefficient can be minimized, and the liquid phase temperature can be controlled to be low. In the glass 10, the content of SrO is preferably 0.01% or more and 5% or less, more preferably 0.1% or more and 3% or less, more preferably 0.15% or more and 2% or less, more preferably 0.2% or more and 1.3% or less, more preferably 0.25% or more and 1% or less, and more preferably 0.3% or more and 0.5% or less in terms of mol % on an oxide basis. When the content of SrO is within this range, the manufacturing can be facilitated while deflection is minimized.

BaO

[0044] BaO has an effect of improving the solubility of glass and reducing the liquid phase temperature. Therefore, the glass 10 may not contain BaO (the content of BaO is 0 mol %), but may contain BaO. By setting the content of BaO to 5% or less, an increase in the linear thermal expansion coefficient can be minimized, and the liquid phase temperature can be controlled to be low. In the glass 10, the content of BaO is preferably 0.01% or more and 5% or less, more preferably 0.1% or more and 3% or less, more preferably 0.15% or more and 2% or less, more preferably 0.2% or more and 1.3% or less, more preferably 0.25% or more and 1% or less, and more preferably 0.3% or more and 0.5% or less in terms of mol % on an oxide basis. When the content of BaO is within this range, the manufacturing can be facilitated while deflection is minimized.

Li.SUB.2.O

[0045] Among alkali metal oxides, Li.sub.2O has an effect of improving solubility without reducing the linear thermal expansion coefficient. Therefore, the glass 10 may not contain Li.sub.2O (the content of Li.sub.2O is 0 mol %), but may contain Li.sub.2O. By setting the content of Li.sub.2O to 5% or less, the Young's modulus can be increased, and an increase in the linear thermal expansion coefficient can be minimized. In the glass 10, the content of Li.sub.2O is preferably 0.01% or more and 5% or less, more preferably 0.1% or more and 4% or less, more preferably 0.15% or more and 3% or less, more preferably 0.2% or more and 2% or less, more preferably 0.25% or more and 1.5% or less, and more preferably 0.3% or more and 1% or less in terms of mol % on an oxide basis. When the content of Li.sub.2O is within this range, the manufacturing can be facilitated while deflection is minimized.

Na.SUB.2.O

[0046] Among alkali metal oxides, Na.sub.2O has effects of improving the solubility of glass and reducing the liquid phase temperature. Therefore, the glass 10 may not contain Na.sub.2O (the content of Na.sub.2O is 0 mol %), but may contain Na.sub.2O. By setting the content of Na.sub.2O to 5% or less, the Young's modulus can be increased, and an increase in the linear thermal expansion coefficient can be minimized. In the glass 10, the content of Na.sub.2O is preferably 0.01% or more and 5% or less, more preferably 0.1% or more and 4% or less, more preferably 0.15% or more and 3% or less, more preferably 0.2% or more and 2% or less, more preferably 0.25% or more and 1.5% or less, and more preferably 0.3% or more and 1% or less in terms of mol % on an oxide basis. When the content of Na.sub.2O is within this range, the manufacturing can be facilitated while deflection is minimized.

K.SUB.2.O

[0047] K.sub.2O has an effect of improving the solubility of glass and reducing the liquid phase temperature. Therefore, the glass 10 may not contain K.sub.2O (the content of K.sub.2O is 0 mol %), but may contain K.sub.2O. By setting the content of K.sub.2O to 5% or less, the Young's modulus can be increased, and an increase in the linear thermal expansion coefficient can be minimized. In the glass 10, the content of K.sub.2O is preferably 0.01% or more and 5% or less, more preferably 0.1% or more and 4% or less, more preferably 0.15% or more and 3% or less, more preferably 0.2% or more and 2% or less, more preferably 0.25% or more and 1.5% or less, and more preferably 0.3% or more and 1% or less in terms of mol % on an oxide basis. When the content of K.sub.2O is within this range, the manufacturing can be facilitated while deflection is minimized.

ZnO

[0048] ZnO has effects of improving the solubility of glass and increasing the Young's modulus. Therefore, the glass 10 may not contain ZnO (the content of ZnO is 0 mol %), but may contain ZnO. By setting the content of ZnO to 10% or less, an increase in the linear thermal expansion coefficient can be minimized, and the liquid phase temperature can be controlled. In the glass 10, the content of ZnO is preferably 0.01% or more and 10% or less, more preferably 0.1% or more and 8% or less, more preferably 0.2% or more and 7% or less, more preferably 0.4% or more and 6% or less, more preferably 0.6% or more and 5% or less, more preferably 0.8% or more and 4% or less, and more preferably 1% or more and 3% or less in terms of mol % on an oxide basis. When the content of ZnO is within this range, the manufacturing can be facilitated while deflection is minimized.

[0049] P.sub.2O.sub.5

[0050] P.sub.2O.sub.5 has effects of improving the solubility of glass and reducing the linear thermal expansion coefficient. Therefore, the glass 10 may not contain P.sub.2O.sub.5 (the content of P.sub.2O.sub.5 is 0 mol %), but may contain P.sub.2O.sub.5. By setting the content of P.sub.2O.sub.5 to 5% or less, the Young's modulus can be increased without deteriorating chemical resistance, and an increase in the linear thermal expansion coefficient can be minimized. In the glass 10, the content of P.sub.2O.sub.5 is preferably 0.01% or more and 5% or less, more preferably 0.1% or more and 4% or less, more preferably 0.15% or more and 3% or less, more preferably 0.2% or more and 2% or less, more preferably 0.25% or more and 1.5% or less, and more preferably 0.3% or more and 1% or less in terms of mol % on an oxide basis. When the content of P.sub.2O.sub.5 is within this range, the manufacturing can be facilitated while deflection is minimized.

[0051] ZrO.sub.2

[0052] ZrO.sub.2 can increase the Young's modulus without relatively reducing the linear thermal expansion coefficient. Therefore, the glass 10 may not contain ZrO.sub.2 (the content of ZrO.sub.2 is 0 mol %), but may contain ZrO.sub.2. By setting the content of ZrO.sub.2 to 10% or less, the liquid phase temperature can be controlled. In the glass 10, the content of ZrO.sub.2 is preferably 0.01% or more and 10% or less, more preferably 0.2% or more and 7% or less, more preferably 0.5% or more and 4% or less, more preferably 0.7% or more and 4% or less, and more preferably 1% or more and 2% or less in terms of mol % on an oxide basis. When the content of ZrO.sub.2 is within this range, the manufacturing can be facilitated while deflection is minimized.

TiO.SUB.2

[0053] TiO.sub.2 can increase the Young's modulus without relatively reducing the linear thermal expansion coefficient. Therefore, the glass 10 may not contain TiO.sub.2 (the content of TiO.sub.2 is 0 mol %), but may contain TiO.sub.2. By setting the content of TiO.sub.2 to 10% or less, the liquid phase temperature can be controlled. In the glass 10, the content of TiO.sub.2 is preferably 0.01% or more and 10% or less, more preferably 0.2% or more and 7% or less, more preferably 0.5% or more and 4% or less, more preferably 0.7% or more and 4% or less, and more preferably 1% or more and 2% or less in terms of mol % on an oxide basis. When the content of TiO.sub.2 is within this range, the manufacturing can be facilitated while deflection is minimized.

Y.SUB.2.O.SUB.3

[0054] Y.sub.2O.sub.3 has effects of improving the solubility of glass and increasing the Young's modulus. Therefore, the glass 10 may not contain Y.sub.2O.sub.3 (the content of Y.sub.2O.sub.3 is 0 mol %), but may contain Y.sub.2O.sub.3. By setting the content of Y.sub.2O.sub.3 to 7% or less, the linear thermal expansion coefficient can be controlled. In the glass 10, the content of Y.sub.2O.sub.3 is preferably 0.1% or more and 7% or less, more preferably 0.3% or more and 5% or less, more preferably 0.5% or more and 3% or less, more preferably 0.8% or more and 2.5% or less, and more preferably 1% or more and 2% or less in terms of mol % on an oxide basis. When the content of Y.sub.2O.sub.3 is within this range, the manufacturing can be facilitated while deflection is minimized.

Gd.SUB.2.O.SUB.3

[0055] Gd.sub.2O.sub.3 has effects of improving the solubility of glass and increasing the Young's modulus. Therefore, the glass 10 may not contain Gd.sub.2O.sub.3 (the content of Gd.sub.2O.sub.3 is 0 mol %), but may contain Gd.sub.2O.sub.3. By setting the content of Gd.sub.2O.sub.3 to 7% or less, the linear thermal expansion coefficient can be controlled. In the glass 10, the content of Gd.sub.2O.sub.3 is preferably 0.1% or more and 7% or less, more preferably 0.3% or more and 5% or less, more preferably 0.5% or more and 3% or less, more preferably 0.8% or more and 2.5% or less, and more preferably 1% or more and 2% or less in terms of molt on an oxide basis. When the content of Gd.sub.2O.sub.3 is within this range, the manufacturing can be facilitated while deflection is minimized.

La.SUB.2.O.SUB.3

[0056] La.sub.2O.sub.3 has effects of improving the solubility of glass and increasing the Young's modulus. Therefore, the glass 10 may not contain La.sub.2O.sub.3 (the content of La.sub.2O.sub.3 is 0 mol %), but may contain La.sub.2O.sub.3. By setting the content of La.sub.2O.sub.3 to 7% or less, the linear thermal expansion coefficient can be controlled. In the glass 10, the content of La.sub.2O.sub.3 is preferably 0.1% or more and 7% or less, more preferably 0.3% or more and 5% or less, more preferably 0.5% or more and 3% or less, more preferably 0.8% or more and 2.5% or less, and more preferably 1% or more and 2% or less in terms of mol % on an oxide basis. When the content of La.sub.2O.sub.3 is within this range, the manufacturing can be facilitated while deflection is minimized.

WO.SUB.3

[0057] WO.sub.3 has effects of improving the solubility of glass and increasing the Young's modulus. Therefore, the glass 10 may not contain WO.sub.3 (the content of WO.sub.3 is 0 mol %), but may contain WO.sub.3. By setting the content of WO.sub.3 to 7% or less, an increase in the linear thermal expansion coefficient can be minimized, and the liquid phase temperature can be controlled. In the glass 10, the content of WO.sub.3 is preferably 0.1% or more and 7% or less, more preferably 0.3% or more and 5% or less, more preferably 0.5% or more and 3% or less, more preferably 0.8% or more and 2.5% or less, and more preferably 1% or more and 2% or less in terms of mol % on an oxide basis. When the content of WO.sub.3 is within this range, the manufacturing can be facilitated while deflection is minimized.

Ta.SUB.2.O.SUB.5

[0058] Ta.sub.2O.sub.5 has effects of reducing the linear thermal expansion coefficient and increasing the Young's modulus. Therefore, the glass 10 may not contain Ta.sub.2O.sub.5 (the content of Ta.sub.2O.sub.5 is 0 mol %), but may contain Ta.sub.2O.sub.5. By setting the content of Ta.sub.2O.sub.5 to 10% or less, the liquid phase temperature can be controlled. In the glass 10, the content of Ta.sub.2O.sub.5 is preferably 0.1% or more and 10% or less, more preferably 0.5% or more and 5% or less, more preferably 1% or more and 4% or less, more preferably 1.5% or more and 3.5% or less, and more preferably 2% or more and 3% or less in terms of mol % on an oxide basis. When the content of Ta.sub.2O.sub.5 is within this range, the manufacturing can be facilitated while deflection is minimized.

MnO

[0059] MnO has an effect of increasing the Young's modulus. However, MnO may increase the liquid phase temperature, and even a small amount of MnO causes the glass to be darkly colored from dark brown to black. Therefore, it is preferable that the glass 10 does not contain MnO. In the glass 10, the content of MnO is preferably 0.1% or less, more preferably 0.001% or more and 0.05% or less, and still more preferably 0.005% or more and 0.01% or less in terms of mol % on an oxide basis. When the content of MnO is within this range, a decrease in light transmittance can be minimized.

PbO

[0060] PbO is an oxide having a high environmental load although having an effect of increasing the Young's modulus. Therefore, it is preferable that the glass 10 does not contain PbO. In the glass 10, the content of PbO is preferably 0.1% or less, more preferably 0.05% or less, and still more preferably 0.01% or less in terms of mol % on an oxide basis. When the content of PbO is within this range, the environmental load can be reduced.

Fe.SUB.2.O.SUB.3

[0061] The glass 10 preferably does not contain Fe.sub.2O.sub.3. In the glass 10, the content of Fe.sub.2O.sub.3 in the outer percentage is preferably 0.1% or less, more preferably 0.001% or more and 0.05% or less, and still more preferably 0.005% or more and 0.01% or less in terms of mass % on an oxide basis. When the content of Fe.sub.2O.sub.3 is as low as described above, a reduction in light transmittance can be minimized.

[0062] The content of Fe.sub.2O.sub.3 in the outer percentage refers to the ratio of the mass of Fe.sub.2O.sub.3 contained in the glass 10 to the total value of the mass of all the components of the glass 10 excluding Fe.sub.2O.sub.3 in terms of an oxide basis.

Y.SUB.2.O.SUB.3.+Gd.SUB.2.O.SUB.3.+La.SUB.2.O.SUB.3.+Nd.SUB.2.O.SUB.3.+Ta.SUB.2.O.SUB.5.+Nb.SUB.2.O.SUB.5

[0063] In the glass 10, the total content of Y.sub.2O.sub.3, Gd.sub.2O.sub.3, La.sub.2O.sub.3, Nd.sub.2O.sub.3, Ta.sub.2O.sub.5, and Nb.sub.2O.sub.5 (Y.sub.2O.sub.3+Gd.sub.2O.sub.3+La.sub.2O.sub.3+Nd.sub.2O.sub.3+Ta.sub.2O.sub.5+Nb.sub.2O.sub.5) is preferably 0.5% or more, more preferably 1% or more and 10% or less, and more preferably 2% or more and 5% or less in terms of mol % on an oxide basis. When the total content of these components is within this range, the manufacturing can be facilitated while deflection is minimized.

[0064] The glass 10 may not include all of the above-described components, and may include only some of the components. In addition, the glass 10 may contain none of the above-described components. That is, for example, in a case where Y.sub.2O.sub.3 is not contained, (Y.sub.2O.sub.3) in (Y.sub.2O.sub.3+Gd.sub.2O.sub.3+Ta.sub.2O.sub.5+La.sub.2O.sub.3+Nd.sub.2O.sub.3+Nb.sub.2O.sub.5) is considered to be zero, and the same applies to a case where other components are not contained.

[00007]$\left({\mathrm{Al}}_2{O}_3+\mathrm{MgO}\right)/\left({\mathrm{SiO}}_2+{\mathrm{Al}}_2{O}_3+B_2{O}_3+\mathrm{MgO}\right)$

[0065] In the glass 10, the ratio of the total content of Al.sub.2O.sub.3 and MgO to the total content of SiO.sub.2, Al.sub.2O.sub.3, B.sub.2O.sub.3, and MgO ((Al.sub.2O.sub.3+MgO)/(SiO.sub.2+Al.sub.2O.sub.3+B.sub.2O.sub.3+MgO)) is preferably 0.1 or more and 1 or less, more preferably 0.2 or more and 0.8 or less, more preferably 0.28 or more and 0.5 or less, more preferably 0.3 or more and 0.4 or less, and more preferably 0.32 or more and 0.38 or less in terms of mol % on an oxide basis. When the total content of these components is within this range, the Young's modulus can be increased to minimize deflection.

[0066] The glass 10 is not limited to containing all of SiO.sub.2, Al.sub.2O.sub.3, B.sub.2O.sub.3, and MgO. That is, for example, when Al.sub.2O.sub.3 is not contained, (Al.sub.2O.sub.3) in (Al.sub.2O.sub.3+MgO) and (SiO.sub.2+Al.sub.2O.sub.3+B.sub.2O.sub.3+MgO) is considered to be zero, and the same applies to a case where other components are not contained.

[00008]$\left(\mathrm{MgO}\right)/\left(.Math.RO\right)$

[0067] In the glass 10, the ratio ((MgO)/(RO)) of the content of MgO to the total content (RO) of the alkaline earth metal oxide is preferably 0.5 or more and 1 or less, more preferably 0.7 or more and 0.98 or less, more preferably 0.8 or more and 0.97 or less, and more preferably 0.83 or more and 0.96 or less in terms of mol % on an oxide basis. When the total content of these components is within this range, the linear thermal expansion coefficient can be reduced to minimize deflection.

[0068] The glass 10 is not limited to containing an alkaline earth metal oxide such as MgO. For example, in a case where MgO is not contained, MgO in (MgO/RO) is considered to be zero, and in a case where an alkaline earth metal oxide other than MgO is not contained, the content of the alkaline earth metal oxide other than MgO in (MgO/RO) is considered to be zero.

Value of N

[0069] In the glass 10, the number N of oxides having a content of 0.5% or more among the oxides contained in the glass 10 is preferably 5 or more, more preferably 7 or more, more preferably 8 or more, more preferably 9 or more, and more preferably 10 or more. When the number N is as high as described above, the liquid phase temperature can be lowered to facilitate the manufacturing.

[0070] The glass 10 preferably does not contain a sintered body. That is, the glass 10 is preferably glass that is not a sintered body. Here, the sintered body refers to a member in which a plurality of particles are heated at a temperature lower than the melting point to bond the particles to one another. The porosity of the sintered body is high to some extent because the sintered body includes pores, but the porosity of the glass 10 is low because the glass 10 is not a sintered body, and the porosity is thus usually 0%. However, it is allowable to include an inevitable trace amount of pores. The porosity herein is a so-called true porosity, and refers to a value obtained by dividing a sum of volumes of pores (pore) communicating with the outside and pores (pore) not communicating with the outside by a total volume (apparent volume). The porosity can be measured according to, for example, JIS R 1634:1998 Test methods for density and apparent porosity of fine ceramics.

[0071] In addition, it is preferable that glass used for the glass 10 is usually amorphous glass, that is, amorphous solid. In addition, although this glass may be crystallized glass containing crystals on the surface or inside, amorphous glass is preferable from the viewpoint of density. Among the ceramics, those produced by a sintering method are preferably not used because of a low transmittance and a high density.

Shape of Glass

[0072] Next, the shape of the glass 10 will be described. As illustrated in FIG. 1, the glass 10 is a plate-like glass substrate including a surface 12 serving as a principal surface on one side and a surface 14 serving as a principal surface opposite to the surface 12. The surface 14 may be, for example, parallel to the surface 12. Although the glass 10 may have a circular disk shape in plan view, that is, when viewed from a direction orthogonal to the surface 12, the shape is not limited to the disk shape, may be any shape, and may be a polygonal plate such as a rectangle. The shape also includes a shape in which a notch such as a notch or an orientation flat is provided on the outer periphery.

[0073] In addition, a thickness D of the glass 10, that is, the length between the surface 12 and the surface 14 is preferably 0.1 mm or more and 5.0 mm or less, more preferably 0.1 mm or more and 2.0 mm or less, and still more preferably 0.1 mm or more and 0.5 mm or more. By setting the thickness D to 0.1 mm or more, it is possible to prevent the glass 10 from being too thin and to minimize breakage due to deflection or impact. By setting the thickness D to 2.0 mm or less, it is possible to minimize an increase in weight, and by setting the thickness D to 0.5 mm or less, it is possible to further minimize an increase in weight suitably.

Properties of Glass

[0074] Next, properties of the glass 10 other than those described above will be described.

Glass Transition Temperature

[0075] The glass transition temperature of the glass 10 is preferably 600 C. or higher and 850 C. or lower, more preferably 650 C. or higher and 800 C. or lower, more preferably 700 C. or higher and 790 C. or lower, more preferably 705 C. or higher and 780 C. or lower, more preferably 710 C. or higher and 770 C. or lower, more preferably 715 C. or higher and 760 C. or lower, and still more preferably 720 C. or higher and 750 C. or lower. The glass transition temperature can be determined in accordance with the method defined in JIS R3103-3:2001 Viscosity and viscometric fixed temperature of glassPart 3: Determination of dilatometric transformation temperature.

Density

[0076] The density of the glass 10 is preferably 2.45 g/cm.sup.3 or more and 3.0 g/cm.sup.3 or less, more preferably 2.55 g/cm.sup.3 or more and 2.95 g/cm.sup.3 or less, more preferably 2.6 g/cm.sup.3 or more and 2.9 g/cm.sup.3 or less, more preferably 2.65 g/cm.sup.3 or more and 2.85 g/cm.sup.3 or less, and still more preferably 2.7 g/cm.sup.3 or more and 2.8 g/cm.sup.3 or less.

Liquid Phase Viscosity

[0077] A liquid phase viscosity log .sub.L (dPa.Math.s) of the glass 10 is preferably 2 or more and 7 or less, more preferably 2.2 or more and 6.5 or less, more preferably 2.4 or more and 6 or less, more preferably 2.6 or more and 5.5 or less, more preferably 2.8 or more and 5 or less, more preferably 2.9 or more and 4.5 or less, and more preferably 3 or more and 4 or less. The liquid phase viscosity refers to a viscosity of the glass 10 at the liquid phase temperature. Since the liquid phase temperature is relatively high as described above, the manufacturing can be facilitated. In a case where the liquid phase temperature is too high, it is difficult to mold glass. The liquid phase viscosity can be determined by measuring a temperature-viscosity curve by an inner cylinder rotation method or the like and calculating the viscosity at the liquid phase temperature.

Fracture Toughness Value

[0078] A fracture toughness value K.sub.IC of the glass 10 is preferably 0.5 MPa.Math.m.sup.0.5 or more and 2 MPa.Math.m.sup.0.5 or less, more preferably 0.7 MPa.Math.m.sup.0.5 or more and 1.5 MPa.Math.m.sup.0.5 or less, more preferably 0.8 MPa.Math.m.sup.0.5 or more and 1.4 MPa.Math.m.sup.0.5 or less, and still more preferably 0.9 MPa.Math.m.sup.0.5 or more and 1.3 MPa.Math.m.sup.0.5 or less. When the fracture toughness value K.sub.IC is within this range, breakage of the glass 10 can be minimized. When the fracture toughness value K.sub.IC is too high, it is difficult to cut and grind glass. The fracture toughness value K.sub.IC can be measured using a pre-crack introduction fracture test method (Single-Edge-Precracked-Beam (SEPB) method) as defined in, for example, JIS R1607:2015 Testing methods for fracture toughness of fine ceramics at room temperature.

Light Transmittance

[0079] The internal transmittance of the glass 10 having a thickness D of 0.7 mm with respect to light (ultraviolet ray) at a wavelength of 308 nm is preferably 30% or more, more preferably 35% or more, still more preferably 40% or more, still more preferably 45% or more, still more preferably 50% or more, still more preferably 55% or more, and still more preferably 60% or more. When the transmittance with respect to the light at a wavelength of 308 nm is within this range, ultraviolet rays can be appropriately transmitted.

[0080] The internal transmittance of the glass 10 having a thickness D of 0.7 mm with respect to light (infrared ray) at a wavelength of 1064 nm is preferably 80% or more, more preferably 85% or more, and more preferably 90% or more. When the transmittance with respect to the light at a wavelength of 1064 nm is within this range, infrared rays can be appropriately transmitted.

[0081] The transmittance can be measured by measuring a spectral transmittance curve with a spectrophotometer or the like.

Melting Temperature T.SUB.2., Working Temperature T.SUB.3., Molding Temperature T.SUB.4

[0082] A melting temperature T.sub.2 of the glass 10 is preferably 1000 C. or higher and 1550 C. or lower, more preferably 1100 C. or higher and 1500 C. or lower, more preferably 1150 C. or higher and 1450 C. or lower, and more preferably 1200 C. or higher and 1400 C. or lower. The melting temperature T.sub.2 refers to a temperature at which a viscosity is 10.sup.2 dPa.Math.s. When the melting temperature T.sub.2 is relatively low as described above, melting can be facilitated.

[0083] The working temperature T.sub.3 of the glass 10 is preferably 1000 C. or higher and 1400 C. or lower, more preferably 1050 C. or higher and 1350 C. or lower, and more preferably 1100 C. or higher and 1300 C. or lower. The working temperature T.sub.3 refers to a temperature at which a viscosity is 10.sup.3 dPa.Math.s. When the working temperature T.sub.3 is relatively low as described above, molding can be facilitated.

[0084] The molding temperature T.sub.4 of the glass 10 is preferably 900 C. or higher and 1250 C. or lower, more preferably 950 C. or higher and 1200 C. or lower, and more preferably 1000 C. or higher and 1150 C. or lower. The molding temperature T.sub.4 refers to a temperature at which a viscosity is 10.sup.4 dPa.Math.s. When the molding temperature T.sub.4 is relatively low as described above, molding can be facilitated.

[0085] The melting temperature T.sub.2, the working temperature T.sub.3, and the molding temperature T.sub.4 can be measured by an inner cylinder rotation method or the like.

Method for Manufacturing Glass

[0086] The glass 10 may be manufactured by any method, and is manufactured, for example, by the following method. First, a raw material such as silica sand or soda ash, which is a raw material of the compound contained in the glass 10, is heated at a predetermined temperature (for example, 1500 C. to 1600 C.) to be melted. Then, after the melted raw material (glass) is clarified, a molding process of molding the raw material into a plate shape is executed. The molded glass is one that falls within the composition range of the glass 10 described above on an oxide basis. Then, a slow cooling process is performed on the glass molded in the molding process to manufacture the glass 10.

[0087] The method for manufacturing the glass 10 is not limited to the above, and any methods may be adopted. For example, the slow cooling process is not necessary. In addition, various methods can be adopted as the molding process in manufacturing the glass 10, and examples thereof include a melt casting method, a down draw method (for example, an overflow down draw method, a slot down method, a redrawing method, and the like), a float method, a roll-out method, and a press method.

[0088] Next, an example of a manufacturing process in a case where the glass 10 is used for manufacturing FOWLP will be described. In manufacturing FOWLP, a plurality of semiconductor chips are bonded to the glass 10, and the semiconductor chips are covered with an encapsulating material to form an element substrate. Then, the glass 10 and the element substrate are separated, and a surface of the element substrate opposite to a surface of the element substrate on which the semiconductor chips are disposed is bonded to, for example, another glass 10. Then, wiring, solder bumps, and the like are formed on the semiconductor chips, and the element substrate and the glass 10 are separated again. The element substrate is then cut into pieces for each semiconductor chip to obtain a semiconductor device.

Effects

[0089] As described above, the glass 10 according to a first aspect of the present disclosure satisfies Formulae (1) and (2) described above. Since Formulae (1) and (2) are satisfied, the liquid phase temperature can be reduced, and the manufacturing can be facilitated. In addition, for example, a glass having a high Young's modulus and a low thermal expansion coefficient for minimizing deflection is particularly likely to be crystallized and may be difficult to manufacture. In contrast, in the present disclosure, since Formulae (1) and (2) are satisfied, an increase in the liquid phase temperature can be minimized, and the manufacturing can be facilitated.

[0090] A glass 10 according to a second aspect of the present disclosure is the glass 10 according to the first aspect, in which the glass 10 preferably contains, in terms of mol % on an oxide basis, [0091] SiO.sub.2: 40% to 65%, [0092] B.sub.2O.sub.3: 0.01% to 15%, [0093] Al.sub.2O.sub.3+a rare earth oxide: 0% to 20%, and [0094] (Y.sub.2O.sub.3+Gd.sub.2O.sub.3+Ta.sub.2O.sub.5+La.sub.2O.sub.3+Nd.sub.2O.sub.3+Nb.sub.2O.sub.5): 0.5% or more. As a result, since the Young's modulus can be increased, the linear thermal expansion coefficient can be reduced, and the liquid phase temperature can be lowered, the manufacturing can be facilitated while deflection is minimized.

[0095] A glass 10 according to a third aspect of the present disclosure is the glass 10 according to the second aspect, in which the glass 10 preferably contains, in terms of mol % on an oxide basis, [0096] SiO.sub.2: 44% to 64%, [0097] B.sub.2O.sub.3: 1% to 13%, [0098] Al.sub.2O.sub.3: 5% to 20%, and [0099] (Y.sub.2O.sub.3+Gd.sub.2O.sub.3+Ta.sub.2O.sub.5+La.sub.2O.sub.3+Nd.sub.2O.sub.3+Nb.sub.2O.sub.5): 1% or more and 10% or less. As a result, since the Young's modulus can be increased, the linear thermal expansion coefficient can be reduced, and the liquid phase temperature can be lowered, the manufacturing can be facilitated while deflection is minimized.

[0100] A glass 10 according to a fourth aspect of the present disclosure is the glass 10 according to any one of the first aspect to the third aspect, in which it is preferable that, in terms of mol % on an oxide basis,

[00009]$0.1\left\{\left({\mathrm{Al}}_2{O}_3+\mathrm{MgO}\right)/\left({\mathrm{SiO}}_2+{\mathrm{Al}}_2{O}_3+B_2{O}_3+\mathrm{MgO}\right)\right\}1,$$0.5\left(\mathrm{MgO}\right)/\left(.Math.RO\right)1,$

and [0101] 0%Al.sub.2O.sub.3+a rare earth oxide20%. As a result, since the Young's modulus can be increased, the linear thermal expansion coefficient can be reduced, and the liquid phase temperature can be lowered, the manufacturing can be facilitated while deflection is minimized.

[0102] A glass 10 according to a fifth aspect of the present disclosure is the glass 10 according to any one of the first aspect to the fourth aspect, in which it is preferable that a Young's modulus parameter Y calculated by Formula (3) is 0.8 or more, a liquid phase parameter L calculated by Formula (4) is 10.5 or less, and a thermal expansion parameter C calculated by Formula (5) is 0.9 or less. As a result, since the Young's modulus can be increased, the linear thermal expansion coefficient can be reduced, and the liquid phase temperature can be lowered, the manufacturing can be facilitated while deflection is minimized.

[0103] A glass 10 according to a sixth aspect of the present disclosure is the glass 10 according to any one of the first aspect to the fifth aspect, in which it is preferable to use the glass 10 as a substrate. The glass 10 of the present disclosure is suitably used for a substrate.

[0104] A glass 10 according to a seventh aspect of the present disclosure is the glass 10 according to the sixth aspect, in which it is preferable that the glass is used for manufacturing at least one of a fan out wafer level package or a fan out panel level package. The glass 10 is suitably used for these applications.

EXAMPLES

[0105] Next, examples will be described. Tables 1 to 41 are tables showing the properties of the glass of each example. The embodiments may be modified as long as the effects of the invention are obtained.

TABLE-US-00001 TABLE 1 Example Example Example Example Example Example Example Example Example (mol %) 1 2 3 4 5 6 7 8 9 SiO.sub.2 54 54 52 51 53.6 55 54 54 52 Al.sub.2O.sub.3 12 12 14 12.5 12.5 15 12.2 14 14 B.sub.2O.sub.3 7 7 8 9 8 8 7.2 9.1 8.6 MgO 23 21 21.5 22 21 15 23 19 21.5 CaO 1 0.5 0.5 0.3 1 0.2 0.3 0.3 SrO 1 0.5 0.5 0.3 1 0.2 0.3 0.3 BaO 1 0.5 0.5 0.3 1 0.2 0.3 0.3 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1 1 1 1 1 1 TiO.sub.2 1 1 1 1 1 1 1 1 1 Y.sub.2O.sub.3 1 1 2 2 2 1 1 Gd.sub.2O.sub.3 La.sub.2O.sub.3 WO.sub.3 Ta.sub.2O.sub.5 2 2 1 Al.sub.2O.sub.3 + rare earth oxide 12 13 15 14.5 14.5 17 12.2 15 15 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 3 1 2 2 2 1 1 1 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.35 0.37 0.37 0.35 0.32 0.37 0.34 0.37 MgO/RO 1.00 0.88 0.93 0.94 0.96 0.83 0.97 0.95 0.96 N 7 11 10 10 7 10 7 7 7 Young's modulus E (GPa) 98 100 97 99 98 94 95 93 95 Thermal expansion coefficient (ppm/ C.) 3.58 3.86 3.81 4.07 3.92 3.68 3.64 3.55 3.73 Liquid phase temperature T.sub.L ( C.) 1245 1275 1225 1185 1215 1195 1245 1205 1230 13.1 .Math. E+9 T.sub.L 48 49 48 114 76 44 12 21 24 1923 156 .Math. T.sub.L 120 46 103 103 97 154 111 165 112 Young's modulus parameter Y 0.98 0.97 0.97 0.97 0.97 0.95 0.96 0.94 0.96 Liquid phase parameter L 10.0 10.3 10.0 9.6 9.8 10.4 9.9 10.0 9.9 Thermal expansion parameter C 0.73 0.77 0.77 0.82 0.78 0.75 0.74 0.72 0.76 Glass transition point ( C.) 744 750 742 736 745 752 742 745 742 Density (g/cm.sup.3) 2.79 2.89 2.65 2.70 2.68 2.71 2.68 2.59 2.61 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.0 2.8 3.2 3.6 3.3 3.5 3.0 3.4 3.2 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.95 0.96 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 35.3 30.0 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 91.2 91.2 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 1409 1418 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 1250 1257 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 1141 1146 <1200 Deflection determination Deflection determination in high density process x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 10 11 12 13 14 15 16 17 SiO.sub.2 52.1 52 54.8 53.4 50.6 51.6 51 52.5 Al.sub.2O.sub.3 14 14 12.7 13.8 14 14 12.5 12.5 B.sub.2O.sub.3 9 8 8.2 11.0 8 8 8.5 7.5 MgO 20 22.1 20.55 17.8 21.5 21.5 20.5 21.5 CaO 0.3 0.3 0.25 0.5 0.3 0.3 1 1 SrO 0.3 0.3 0.25 0.6 0.3 0.3 1 1 BaO 0.3 0.3 0.25 0.3 0.3 0.5 0.5 Li.sub.2O Na.sub.2O K.sub.2O ZnO 2.5 P.sub.2O.sub.5 ZrO.sub.2 1 1 1 0.9 1 2 1 1 TiO.sub.2 1 1 1 0.5 3 1 1 1 Y.sub.2O.sub.3 2 1 1 1.5 1 1 0.5 1.5 Gd.sub.2O.sub.3 La.sub.2O.sub.3 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16 15 13.7 15.3 15 15 13 14 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 1 1 1.5 1 1 0.5 1.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.38 0.35 0.33 0.38 0.37 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.94 0.96 0.96 0.89 0.90 N 7 7 7 7 7 7 11 10 Young's modulus E (GPa) 97 96 93 91 97 100 95 101 Thermal expansion coefficient (ppm/ C.) 3.77 3.84 3.70 3.59 3.81 3.87 4.25 4.30 Liquid phase temperature T.sub.L ( C.) 1215 1255 1215 1150 1225 1251 1215 1235 13.1 .Math. E+9 T.sub.L 65 16 16 51 48 62 36 101 1923 156 .Math. T.sub.L 120 69 131 213 103 69 45 17 Young's modulus parameter Y 0.97 0.97 0.95 0.93 0.98 0.99 0.95 0.97 Liquid phase parameter L 9.9 9.9 9.9 9.6 10.3 10.0 9.6 9.8 Thermal expansion parameter C 0.77 0.76 0.74 0.73 0.77 0.77 0.81 0.82 Glass transition point ( C.) 745 743 744 735 742 746 719 737 Density (g/cm.sup.3) 2.68 2.63 2.60 2.58 2.65 2.71 2.69 2.84 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.3 3.0 3.3 3.9 3.2 3.0 3.3 3.1 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x Manufacturability determination

TABLE-US-00002 TABLE 2 Example Example Example Example Example Example Example Example Example (mol %) 18 19 20 21 22 23 24 25 26 SiO.sub.2 51.4 51 51 51.2 49 50.8 54 54 54 Al.sub.2O.sub.3 12.3 13 12 12.1 14 12.9 12 12 12 B.sub.2O.sub.3 8 7 7 8.0 8.0 7.0 7 7 7 MgO 21 21 21 21.4 21.4 22.4 23 23 23 CaO 1.3 1 2 1.3 1.3 1.0 SrO 1.3 1 1 1.3 1.3 1.0 BaO 0.3 1 1 0.6 0.6 1.0 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1.0 1.0 1.0 0.5 1 1 TiO.sub.2 1 1 1 1.0 1.0 1.0 1.5 0.5 1.5 Y.sub.2O.sub.3 2.4 3 3 2.0 2.0 2.0 Gd.sub.2O.sub.3 La.sub.2O.sub.3 WO.sub.3 Ta.sub.2O.sub.5 2 2.5 1.5 Al.sub.2O.sub.3 + rare earth oxide 14.7 16 15 14.1 16.0 14.9 12 12 12 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2.4 3 3 2 2 2 2 2.5 1.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.37 0.36 0.36 0.38 0.38 0.36 0.36 0.36 MgO/RO 0.88 0.88 0.84 0.87 0.87 0.88 1.00 1.00 1.00 N 9 10 10 10 10 10 7 7 7 Young's modulus E (GPa) 99 100 100 97 100 98 98 99 99 Thermal expansion coefficient (ppm/ C.) 4.22 4.36 4.47 4.21 4.25 4.30 3.60 3.61 3.65 Liquid phase temperature T.sub.L ( C.) 1175 1195 1175 1185 1205 1205 1277 1273 1236 13.1 .Math. E+9 T.sub.L 132 124 140 92 107 89 21 36 64 1923 156 .Math. T.sub.L 89 48 51 82 56 47 84 87 117 Young's modulus parameter Y 0.99 1.00 1.00 0.98 1.00 0.99 0.97 0.98 0.97 Liquid phase parameter L 9.6 9.9 9.7 9.6 9.7 9.8 10.0 9.9 10.0 Thermal expansion parameter C 0.86 0.87 0.90 0.86 0.86 0.86 0.72 0.73 0.73 Glass transition point ( C.) 734 744 739 732 733 739 732 745 732 Density (g/cm.sup.3) 2.76 2.82 2.82 2.74 2.76 2.75 2.79 2.85 2.74 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.7 3.2 3.3 3.2 3.0 3.4 2.8 2.8 3.1 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.95 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 33.8 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 90.6 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 1359 <1450 <1450 1351 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 1213 <1300 <1300 1204 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 1113 <1200 <1200 1104 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 27 28 29 30 31 32 33 34 SiO.sub.2 54 54 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 12 12 14 14 14 14 14 14 B.sub.2O.sub.3 7 7 9 9 9 9 9 9 MgO 23 23 20 20 20 20 20 20 CaO 0.2 0.2 0.2 0.2 0.2 0.2 SrO 0.2 0.2 0.2 0.2 0.2 0.2 BaO 0.5 0.5 0.5 0.5 0.5 0.5 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1.5 1.5 0.5 0.5 0.5 0.5 0.5 0.5 TiO.sub.2 0.5 1 0.5 0.5 0.5 0.5 0.5 0.5 Y.sub.2O.sub.3 1 1 1 1.5 1.5 2 Gd.sub.2O.sub.3 1 2 1.5 La.sub.2O.sub.3 2 1 1.5 1 WO.sub.3 Ta.sub.2O.sub.5 2 1.5 Al.sub.2O.sub.3 + rare earth oxide 12 12 17 17 17 17 17 17 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 1.5 3 3 3 3 3 3 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 1.00 1.00 0.96 0.96 0.96 0.96 0.96 0.96 N 7 7 9 10 9 9 9 9 Young's modulus E (GPa) 99 99 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 3.65 3.68 4.03 4.07 4.10 3.99 4.05 3.96 Liquid phase temperature T.sub.L ( C.) 1267 1240 1269 1266 1266 1264 1263 1249 13.1 .Math. E+9 T.sub.L 45 68 28 30 29 32 33 47 1923 156 .Math. T.sub.L 86 110 25 22 17 36 28 57 Young's modulus parameter Y 0.98 0.98 0.97 0.97 0.97 0.97 0.97 0.98 Liquid phase parameter L 9.9 10.0 9.5 9.5 9.5 9.6 9.6 9.6 Thermal expansion parameter C 0.73 0.73 0.80 0.80 0.80 0.80 0.80 0.79 Glass transition point ( C.) 744 734 740 733 733 740 733 740 Density (g/cm.sup.3) 2.80 2.75 2.84 2.85 2.86 2.82 2.83 2.80 Liquid phase viscosity log .sub.L (dPa .Math. s) 2.9 3.1 2.9 2.9 2.9 2.9 2.9 3.0 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x Manufacturability determination

TABLE-US-00003 TABLE 3 Example Example Example Example Example Example Example Example Example (mol %) 35 36 37 38 39 40 41 42 43 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 SrO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 BaO 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 TiO.sub.2 0.5 1 1 1 1 1 1.5 1.5 1.5 Y.sub.2O.sub.3 2 1 1 1.5 1.5 2.5 1 1 2 Gd.sub.2O.sub.3 1 1.5 1 1 La.sub.2O.sub.3 1.5 1 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 17 16.5 16.5 16.5 16.5 16.5 16 16 16 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 3 2.5 2.5 2.5 2.5 2.5 2 2 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 9 9 9 9 9 8 9 8 Young's modulus E (GPa) 98 98 98 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 3.99 3.95 4.01 3.91 3.95 3.84 3.87 3.91 3.79 Liquid phase temperature T.sub.L ( C.) 1249 1258 1255 1251 1250 1233 1258 1255 1235 13.1 .Math. E+9 T.sub.L 47 34 36 41 42 59 29 32 53 1923 156 .Math. T.sub.L 51 49 43 61 57 91 61 58 96 Young's modulus parameter Y 0.98 0.97 0.97 0.97 0.97 0.97 0.96 0.96 0.96 Liquid phase parameter L 9.6 9.7 9.7 9.7 9.7 9.9 9.9 9.9 10.0 Thermal expansion parameter C 0.79 0.79 0.79 0.78 0.78 0.77 0.77 0.77 0.76 Glass transition point ( C.) 733 733 726 733 726 733 730 725 730 Density (g/cm.sup.3) 2.81 2.79 2.81 2.77 2.78 2.73 2.75 2.75 2.71 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.0 2.9 3.0 3.0 3.0 3.1 2.9 3.0 3.1 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 44 45 46 47 48 49 50 51 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 SrO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 BaO 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1 1 1 1 1 TiO.sub.2 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Y.sub.2O.sub.3 1 1 1.5 1.5 Gd.sub.2O.sub.3 1 1.5 2.5 1.5 1 La.sub.2O.sub.3 2.5 1.5 1 1.5 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16.5 16.5 16.5 16.5 16.5 16.5 16.5 16.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 8 9 9 8 9 9 9 9 Young's modulus E (GPa) 98 98 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 4.06 4.09 4.11 4.15 3.98 4.03 3.94 3.98 Liquid phase temperature T.sub.L ( C.) 1256 1253 1252 1252 1235 1230 1235 1233 13.1 .Math. E+9 T.sub.L 42 45 45 46 64 67 64 66 1923 156 .Math. T.sub.L 34 32 30 25 67 64 74 70 Young's modulus parameter Y 0.97 0.97 0.97 0.97 0.97 0.97 0.97 0.97 Liquid phase parameter L 9.5 9.5 9.5 9.5 9.6 9.6 9.7 9.7 Thermal expansion parameter C 0.80 0.80 0.80 0.80 0.79 0.79 0.79 0.79 Glass transition point ( C.) 740 733 733 733 740 733 740 733 Density (g/cm.sup.3) 2.84 2.85 2.85 2.86 2.80 2.81 2.78 2.79 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.0 3.0 3.0 3.0 3.1 3.2 3.1 3.1 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x Manufacturability determination

TABLE-US-00004 TABLE 4 Example Example Example Example Example Example Example Example Example (mol %) 52 53 54 55 56 57 58 59 60 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 SrO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 BaO 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1 1 1 1 1 1 TiO.sub.2 0.5 1 1 1 1 1 1 1.5 1.5 Y.sub.2O.sub.3 2.5 1 1 2 Gd.sub.2O.sub.3 1 2 1 1.5 La.sub.2O.sub.3 2 1 1 1.5 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16.5 16 16 16 16 16 16 15.5 15.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2.5 2 2 2 2 2 2 1.5 1.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 8 8 9 8 9 9 8 8 8 Young's modulus E (GPa) 98 98 98 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 3.86 3.98 4.01 4.05 3.90 3.93 3.82 3.89 3.95 Liquid phase temperature T.sub.L ( C.) 1219 1234 1230 1230 1223 1218 1205 1228 1223 13.1 .Math. E+9 T.sub.L 80 59 63 63 71 75 89 61 66 1923 156 .Math. T.sub.L 102 68 67 62 92 91 122 87 84 Young's modulus parameter Y 0.98 0.96 0.96 0.96 0.97 0.97 0.97 0.96 0.96 Liquid phase parameter L 9.8 9.7 9.7 9.7 9.8 9.8 9.9 9.9 9.9 Thermal expansion parameter C 0.78 0.78 0.78 0.78 0.77 0.77 0.77 0.77 0.77 Glass transition point ( C.) 740 732 725 726 732 725 732 730 724 Density (g/cm.sup.3) 2.74 2.79 2.80 2.81 2.75 2.76 2.72 2.75 2.76 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.3 3.1 3.2 3.2 3.2 3.3 3.4 3.2 3.2 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 61 62 63 64 65 66 67 68 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 SrO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 BaO 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1.5 1.5 1.5 1.5 1.5 1.5 1.5 TiO.sub.2 1.5 0.5 0.5 0.5 0.5 0.5 0.5 1 Y.sub.2O.sub.3 1.5 1 1 2 Gd.sub.2O.sub.3 1 2 1 La.sub.2O.sub.3 2 1 1 1.5 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 15.5 16 16 16 16 16 16 15.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 1.5 2 2 2 2 2 2 1.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 8 8 9 8 9 9 8 8 Young's modulus E (GPa) 98 99 99 99 99 99 99 98 Thermal expansion coefficient (ppm/ C.) 3.78 4.00 4.04 4.07 3.92 3.96 3.85 3.92 Liquid phase temperature T.sub.L ( C.) 1222 1255 1252 1251 1234 1230 1219 1234 13.1 .Math. E+9 T.sub.L 68 45 48 49 67 71 82 62 1923 156 .Math. T.sub.L 111 43 42 37 77 76 104 77 Young's modulus parameter Y 0.96 0.97 0.97 0.97 0.97 0.97 0.98 0.96 Liquid phase parameter L 10.0 9.6 9.6 9.6 9.7 9.7 9.8 9.8 Thermal expansion parameter C 0.76 0.79 0.79 0.79 0.78 0.78 0.77 0.77 Glass transition point ( C.) 730 740 733 733 740 733 740 733 Density (g/cm.sup.3) 2.69 2.80 2.81 2.82 2.76 2.77 2.72 2.75 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.2 3.0 3.0 3.0 3.1 3.2 3.2 3.1 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x Manufacturability determination

TABLE-US-00005 TABLE 5 Example Example Example Example Example Example Example Example Example (mol %) 69 70 71 72 73 74 75 76 77 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 6 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 SrO 0.2 0.2 0.2 0.2 0.2 0.3 0.3 0.3 0.3 BaO 0.5 0.5 0.5 0.5 0.5 0.4 0.4 0.4 0.4 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1.5 1.5 1.5 1.5 1.5 0.5 0.5 0.5 0.5 TiO.sub.2 1 1 1.5 1.5 1.5 0.5 0.5 0.5 0.5 Y.sub.2O.sub.3 1.5 1 1 1 1 1.5 Gd.sub.2O.sub.3 1.5 1 1 2 La.sub.2O.sub.3 1 2 1 1.5 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 15.5 15.5 15 15 15 17 17 17 17 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 1.5 1.5 1 1 1 3 3 3 3 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 8 8 8 8 8 8 9 8 8 Young's modulus E (GPa) 98 98 98 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 3.97 3.80 3.84 3.88 3.76 4.03 4.07 4.10 3.99 Liquid phase temperature T.sub.L ( C.) 1229 1221 1227 1223 1222 1264 1261 1261 1259 13.1 .Math. E+9 T.sub.L 66 75 64 68 70 33 35 35 37 1923 156 .Math. T.sub.L 74 108 97 96 114 30 27 22 41 Young's modulus parameter Y 0.96 0.97 0.96 0.96 0.96 0.97 0.97 0.97 0.98 Liquid phase parameter L 9.8 10.0 10.0 10.0 10.1 9.5 9.5 9.5 9.6 Thermal expansion parameter C 0.77 0.76 0.76 0.76 0.75 0.80 0.80 0.80 0.80 Glass transition point ( C.) 726 733 730 725 730 739 733 733 739 Density (g/cm.sup.3) 2.77 2.70 2.71 2.72 2.67 2.84 2.85 2.86 2.82 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.2 3.2 3.2 3.2 3.2 2.9 2.9 2.9 2.9 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 78 79 80 81 82 83 84 85 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 SrO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 BaO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 TiO.sub.2 0.5 0.5 0.5 1 1 1 1 1 Y.sub.2O.sub.3 1.5 2 2 1 1 1.5 1.5 2.5 Gd.sub.2O.sub.3 1.5 1 1.5 1 La.sub.2O.sub.3 1 1.5 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 17 17 17 16.5 16.5 16.5 16.5 16.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 3 3 3 2.5 2.5 2.5 2.5 2.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 8 8 8 8 8 8 8 7 Young's modulus E (GPa) 98 98 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 4.05 3.96 3.99 3.95 4.01 3.91 3.95 3.84 Liquid phase temperature T.sub.L ( C.) 1258 1243 1243 1253 1250 1247 1246 1227 13.1 .Math. E+9 T.sub.L 38 54 54 39 41 46 47 66 1923 156 .Math. T.sub.L 33 63 58 53 48 65 61 97 Young's modulus parameter Y 0.97 0.98 0.98 0.97 0.97 0.97 0.97 0.97 Liquid phase parameter L 9.6 9.6 9.6 9.7 9.7 9.7 9.7 9.8 Thermal expansion parameter C 0.80 0.79 0.79 0.79 0.79 0.78 0.78 0.77 Glass transition point ( C.) 733 739 733 733 726 733 726 733 Density (g/cm.sup.3) 2.83 2.80 2.81 2.79 2.80 2.77 2.78 2.73 Liquid phase viscosity log .sub.L (dPa .Math. s) 2.9 3.1 3.1 3.0 3.0 3.0 3.0 3.2 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x Manufacturability determination

TABLE-US-00006 TABLE 6 Example Example Example Example Example Example Example Example Example (mol %) 86 87 88 89 90 91 92 93 94 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 SrO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 BaO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 0.5 0.5 0.5 0.5 0.5 0.5 1 1 1 TiO.sub.2 1.5 1.5 1.5 1.5 1.5 1.5 0.5 0.5 0.5 Y.sub.2O.sub.3 1 1 2 Gd.sub.2O.sub.3 1 2 1 1 1.5 La.sub.2O.sub.3 2 1 1 2.5 1.5 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16 16 16 16 16 16 16.5 16.5 16.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 2 2 2 2 2 2.5 2.5 2.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 7 8 7 8 8 7 7 8 8 Young's modulus E (GPa) 98 98 98 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 3.95 3.99 4.02 3.87 3.91 3.79 4.06 4.09 4.11 Liquid phase temperature T.sub.L ( C.) 1278 1275 1275 1253 1250 1228 1252 1249 1249 13.1 .Math. E+9 T.sub.L 9 12 11 35 38 60 46 49 49 1923 156 .Math. T.sub.L 29 26 20 66 63 103 38 35 33 Young's modulus parameter Y 0.96 0.96 0.96 0.96 0.96 0.96 0.97 0.97 0.97 Liquid phase parameter L 9.7 9.7 9.7 9.8 9.8 9.9 9.5 9.5 9.5 Thermal expansion parameter C 0.78 0.78 0.78 0.77 0.77 0.76 0.80 0.80 0.80 Glass transition point ( C.) 731 725 726 731 725 731 739 733 733 Density (g/cm.sup.3) 2.78 2.79 2.80 2.74 2.75 2.70 2.84 2.85 2.85 Liquid phase viscosity log .sub.L (dPa .Math. s) 2.8 2.8 2.8 3.0 3.0 3.2 3.0 3.0 3.0 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 95 96 97 98 99 100 101 102 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 SrO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 BaO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1 1 1 1 1 TiO.sub.2 0.5 0.5 0.5 0.5 0.5 0.5 1 1 Y.sub.2O.sub.3 1 1 1.5 1.5 2.5 Gd.sub.2O.sub.3 2.5 1.5 1 1 La.sub.2O.sub.3 1.5 1 2 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16.5 16.5 16.5 16.5 16.5 16.5 16 16 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2.5 2.5 2.5 2.5 2.5 2.5 2 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 7 8 8 8 8 7 7 8 Young's modulus E (GPa) 98 98 98 98 98 99 98 98 Thermal expansion coefficient (ppm/ C.) 4.14 3.98 4.03 3.94 3.97 3.86 3.98 4.01 Liquid phase temperature T.sub.L ( C.) 1248 1230 1226 1230 1228 1214 1231 1227 13.1 .Math. E+9 T.sub.L 50 69 72 69 71 86 63 67 1923 156 .Math. T.sub.L 29 72 68 78 75 107 72 70 Young's modulus parameter Y 0.97 0.97 0.97 0.98 0.98 0.98 0.97 0.96 Liquid phase parameter L 9.5 9.6 9.6 9.7 9.7 9.8 9.7 9.7 Thermal expansion parameter C 0.80 0.79 0.79 0.79 0.79 0.78 0.78 0.78 Glass transition point ( C.) 733 739 733 739 733 739 733 726 Density (g/cm.sup.3) 2.86 2.80 2.81 2.78 2.79 2.74 2.79 2.80 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.0 3.2 3.2 3.2 3.2 3.3 3.2 3.2 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x Manufacturability determination

TABLE-US-00007 TABLE 7 Example Example Example Example Example Example Example Example Example (mol %) 103 104 105 106 107 108 109 110 111 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 SrO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 BaO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1 1 1 1 1.5 1.5 TiO.sub.2 1 1 1 1 1.5 1.5 1.5 0.5 0.5 Y.sub.2O.sub.3 1 1 2 1.5 Gd.sub.2O.sub.3 2 1 1.5 1 La.sub.2O.sub.3 1 1.5 2 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16 16 16 16 15.5 15.5 15.5 16 16 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 2 2 2 1.5 1.5 1.5 2 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 7 8 8 7 7 7 7 7 8 Young's modulus E (GPa) 98 98 98 98 98 98 98 99 99 Thermal expansion coefficient (ppm/ C.) 4.05 3.90 3.93 3.82 3.89 3.95 3.78 4.00 4.04 Liquid phase temperature T.sub.L ( C.) 1226 1219 1214 1201 1224 1219 1217 1253 1249 13.1 .Math. E+9 T.sub.L 67 76 80 94 66 71 73 48 51 1923 156 .Math. T.sub.L 65 96 95 127 91 88 117 46 44 Young's modulus parameter Y 0.96 0.97 0.97 0.97 0.96 0.96 0.96 0.97 0.97 Liquid phase parameter L 9.7 9.8 9.8 9.9 9.8 9.8 10.0 9.6 9.6 Thermal expansion parameter C 0.78 0.78 0.78 0.77 0.77 0.77 0.76 0.79 0.79 Glass transition point ( C.) 726 733 726 733 730 725 730 740 733 Density (g/cm.sup.3) 2.81 2.75 2.76 2.71 2.74 2.76 2.69 2.80 2.81 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.2 3.3 3.3 3.4 3.2 3.3 3.3 3.0 3.0 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 112 113 114 115 116 117 118 119 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 SrO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 BaO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 TiO.sub.2 0.5 0.5 0.5 0.5 1 1 1 1.5 Y.sub.2O.sub.3 1 1 2 1.5 Gd.sub.2O.sub.3 2 1 1.5 La.sub.2O.sub.3 1 1.5 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16 16 16 16 15.5 15.5 15.5 15 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 2 2 2 1.5 1.5 1.5 1 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 7 8 8 7 7 7 7 7 Young's modulus E (GPa) 99 99 99 99 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 4.07 3.92 3.96 3.84 3.92 3.97 3.80 3.84 Liquid phase temperature T.sub.L ( C.) 1249 1231 1227 1216 1232 1227 1219 1225 13.1 .Math. E+9 T.sub.L 52 70 74 86 64 69 78 68 1923 156 .Math. T.sub.L 39 80 79 108 79 76 111 99 Young's modulus parameter Y 0.97 0.98 0.97 0.98 0.97 0.97 0.97 0.96 Liquid phase parameter L 9.6 9.7 9.7 9.8 9.8 9.8 9.9 9.9 Thermal expansion parameter C 0.79 0.78 0.78 0.77 0.77 0.77 0.76 0.76 Glass transition point ( C.) 733 740 733 740 733 726 733 731 Density (g/cm.sup.3) 2.82 2.76 2.77 2.72 2.75 2.76 2.69 2.71 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.0 3.1 3.2 3.3 3.1 3.2 3.3 3.2 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x Manufacturability determination

TABLE-US-00008 TABLE 8 Example Example Example Example Example Example Example Example Example (mol %) 120 121 122 123 124 125 126 127 128 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 SrO 0.3 0.3 0.4 0.4 0.4 0.4 0.4 0.4 0.4 BaO 0.4 0.4 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1.5 1.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 TiO.sub.2 1.5 1.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Y.sub.2O.sub.3 1 1 1 1 1.5 1.5 2 2 Gd.sub.2O.sub.3 1 1 2 1.5 1 La.sub.2O.sub.3 2 1 1.5 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 15 15 17 17 17 17 17 17 17 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 1 1 3 3 3 3 3 3 3 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 7 7 8 9 8 8 8 8 8 Young's modulus E (GPa) 98 98 98 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 3.87 3.76 4.03 4.07 4.10 3.99 4.05 3.95 3.99 Liquid phase temperature T.sub.L ( C.) 1220 1218 1264 1261 1261 1260 1258 1243 1243 13.1 .Math. E+9 T.sub.L 72 74 33 36 35 38 38 55 54 1923 156 .Math. T.sub.L 98 118 30 27 22 40 33 63 58 Young's modulus parameter Y 0.96 0.96 0.98 0.98 0.97 0.98 0.98 0.98 0.98 Liquid phase parameter L 9.9 10.1 9.5 9.5 9.5 9.5 9.5 9.6 9.6 Thermal expansion parameter C 0.76 0.75 0.80 0.80 0.80 0.80 0.80 0.79 0.79 Glass transition point ( C.) 725 731 738 732 732 738 732 738 732 Density (g/cm.sup.3) 2.71 2.67 2.84 2.85 2.85 2.82 2.83 2.80 2.81 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.2 3.3 2.9 2.9 2.9 2.9 2.9 3.1 3.1 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 129 130 131 132 133 134 135 136 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 SrO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 BaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 TiO.sub.2 1 1 1 1 1 1.5 1.5 1.5 Y.sub.2O.sub.3 1 1 1.5 1.5 2.5 Gd.sub.2O.sub.3 1.5 1 1 2 La.sub.2O.sub.3 1.5 1 2 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16.5 16.5 16.5 16.5 16.5 16 16 16 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2.5 2.5 2.5 2.5 2.5 2 2 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 8 8 8 8 7 7 8 7 Young's modulus E (GPa) 98 98 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 3.95 4.01 3.91 3.95 3.84 3.95 3.98 4.02 Liquid phase temperature T.sub.L ( C.) 1253 1250 1247 1246 1227 1278 1276 1276 13.1 .Math. E+9 T.sub.L 40 42 46 47 66 10 12 12 1923 156 .Math. T.sub.L 53 48 65 61 97 29 26 20 Young's modulus parameter Y 0.97 0.97 0.97 0.97 0.97 0.96 0.96 0.96 Liquid phase parameter L 9.6 9.6 9.7 9.7 9.8 9.7 9.7 9.7 Thermal expansion parameter C 0.79 0.79 0.78 0.78 0.78 0.78 0.78 0.78 Glass transition point ( C.) 733 727 733 727 733 731 726 726 Density (g/cm.sup.3) 2.79 2.80 2.77 2.78 2.73 2.78 2.79 2.80 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.0 3.0 3.0 3.0 3.2 2.8 2.8 2.8 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x Manufacturability determination

TABLE-US-00009 TABLE 9 Example Example Example Example Example Example Example Example Example (mol %) 137 138 139 140 141 142 143 144 145 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 SrO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 BaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 0.5 0.5 0.5 1 1 1 1 1 1 TiO.sub.2 1.5 1.5 4.5 0.5 0.5 0.5 0.5 0.5 0.5 Y.sub.2O.sub.3 1 1 2 1 1 Gd.sub.2O.sub.3 1 1 1.5 2.5 1.5 La.sub.2O.sub.3 1 2.5 1.5 1 1.5 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16 16 16 16.5 16.5 16.5 16.5 16.5 16.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 2 2 2.5 2.5 2.5 2.5 2.5 2.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 8 8 7 7 8 8 7 8 8 Young's modulus E (GPa) 98 98 98 98 98 98 98 99 98 Thermal expansion coefficient (ppm/ C.) 3.87 3.91 3.79 4.06 4.09 4.11 4.14 3.98 4.03 Liquid phase temperature T.sub.L ( C.) 1253 1250 1228 1252 1249 1248 1248 1230 1226 13.1 .Math. E+9 T.sub.L 36 38 61 47 49 50 50 69 73 1923 156 .Math. T.sub.L 66 63 103 38 36 34 29 72 68 Young's modulus parameter Y 0.96 0.96 0.96 0.97 0.97 0.97 0.97 0.98 0.98 Liquid phase parameter L 9.8 9.8 9.9 9.5 9.5 9.5 9.5 9.6 9.6 Thermal expansion parameter C 0.77 0.77 0.76 0.80 0.80 0.80 0.80 0.79 0.79 Glass transition point ( C.) 731 726 731 738 732 732 733 738 732 Density (g/cm.sup.3) 2.74 2.75 2.70 2.84 2.85 2.85 2.86 2.80 2.81 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.0 3.0 3.2 3.0 3.0 3.0 3.0 3.2 3.2 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 146 147 148 149 150 151 152 153 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 SrO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 BaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1 1 1 1 1 TiO.sub.2 0.5 0.5 0.5 1 1 1 1 1 Y.sub.2O.sub.3 1.5 1.5 2.5 1 1 Gd.sub.2O.sub.3 1 1 2 1 La.sub.2O.sub.3 1 2 1 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16.5 16.5 16.5 16 16 16 16 16 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2.5 2.5 2.5 2 2 2 2 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 8 8 7 7 8 7 8 8 Young's modulus E (GPa) 99 98 99 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 3.94 3.97 3.86 3.97 4.01 4.05 3.90 3.93 Liquid phase temperature T.sub.L ( C.) 1231 1228 1214 1231 1227 1226 1219 1214 13.1 .Math. E+9 T.sub.L 69 71 86 63 67 68 76 80 1923 156 .Math. T.sub.L 78 75 107 72 70 66 96 95 Young's modulus parameter Y 0.98 0.98 0.98 0.97 0.97 0.97 0.97 0.97 Liquid phase parameter L 9.6 9.6 9.7 9.6 9.6 9.6 9.8 9.8 Thermal expansion parameter C 0.79 0.79 0.78 0.78 0.78 0.78 0.78 0.78 Glass transition point ( C.) 738 732 738 733 726 727 733 726 Density (g/cm.sup.3) 2.78 2.79 2.74 2.79 2.80 2.81 2.75 2.76 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.2 3.2 3.3 3.2 3.2 3.2 3.3 3.3 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x Manufacturability determination

TABLE-US-00010 TABLE 10 Example Example Example Example Example Example Example Example Example (mol %) 154 155 156 157 158 159 160 161 162 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 SrO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 BaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1 1.5 1.5 1.5 1.5 1.5 TiO.sub.2 1 1.5 1.5 1.5 0.5 0.5 0.5 0.5 0.5 Y.sub.2O.sub.3 2 1.5 1 1 Gd.sub.2O.sub.3 1.5 1 2 1 La.sub.2O.sub.3 1.5 2 1 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16 15.5 15.5 15.5 16 16 16 16 16 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 1.5 1.5 1.5 2 2 2 2 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 7 7 7 7 7 8 7 8 8 Young's modulus E (GPa) 98 98 98 98 99 99 99 99 99 Thermal expansion coefficient (ppm/ C.) 3.82 3.89 3.95 3.78 4.00 4.04 4.07 3.92 3.96 Liquid phase temperature T.sub.L ( C.) 1201 1224 1219 1217 1253 1249 1249 1231 1227 13.1 .Math. E+9 T.sub.L 95 66 71 74 48 52 52 70 74 1923 156 .Math. T.sub.L 127 91 88 116 46 44 39 80 79 Young's modulus parameter Y 0.97 0.96 0.96 0.96 0.97 0.97 0.97 0.98 0.98 Liquid phase parameter L 9.9 9.8 9.8 10.0 9.6 9.6 9.6 9.7 9.7 Thermal expansion parameter C 0.77 0.77 0.77 0.76 0.79 0.79 0.79 0.78 0.78 Glass transition point ( C.) 733 730 726 730 739 733 733 739 733 Density (g/cm.sup.3) 2.71 2.74 2.75 2.68 2.80 2.81 2.81 2.76 2.77 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.4 3.2 3.3 3.3 3.0 3.0 3.0 3.1 3.2 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 163 164 165 166 167 168 169 170 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 SrO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.5 BaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.2 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1.5 1.5 1.5 1.5 1.5 1.5 1.5 0.5 TiO.sub.2 0.5 1 1 1 1.5 1.5 1.5 0.5 Y.sub.2O.sub.3 2 1.5 1 1 Gd.sub.2O.sub.3 1.5 1 La.sub.2O.sub.3 1.5 1 2 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16 15.5 15.5 15.5 15 15 15 17 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 1.5 1.5 1.5 1 1 1 3 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 7 7 7 7 7 7 7 9 Young's modulus E (GPa) 99 98 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 3.84 3.92 3.97 3.80 3.84 3.87 3.76 4.03 Liquid phase temperature T.sub.L ( C.) 1216 1232 1227 1219 1225 1220 1218 1267 13.1 .Math. E+9 T.sub.L 87 65 69 79 68 72 75 31 1923 156 .Math. T.sub.L 108 79 76 111 99 98 118 27 Young's modulus parameter Y 0.98 0.97 0.97 0.97 0.96 0.96 0.96 0.98 Liquid phase parameter L 9.8 9.8 9.8 9.9 9.9 9.9 10.0 9.5 Thermal expansion parameter C 0.77 0.77 0.77 0.76 0.76 0.76 0.75 0.80 Glass transition point ( C.) 739 733 727 733 731 726 731 741 Density (g/cm.sup.3) 2.72 2.75 2.76 2.69 2.70 2.71 2.66 2.84 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.3 3.1 3.2 3.3 3.2 3.2 3.3 2.9 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x Manufacturability determination

TABLE-US-00011 TABLE 11 Example Example Example Example Example Example Example Example Example (mol %) 171 172 173 174 175 176 177 178 179 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 SrO 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 BaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 TiO.sub.2 0.5 0.5 0.5 0.5 0.5 0.5 1 1 1 Y.sub.2O.sub.3 1 1 1.5 1.5 2 2 1 1 1.5 Gd.sub.2O.sub.3 1 2 1.5 1 1.5 La.sub.2O.sub.3 1 1.5 1 1.5 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 17 17 17 17 17 17 16.5 16.5 16.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 3 3 3 3 3 3 2.5 2.5 2.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 10 9 9 9 9 9 9 9 9 Young's modulus E (GPa) 98 98 98 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 4.07 4.10 3.99 4.05 3.95 3.99 3.95 4.01 3.91 Liquid phase temperature T.sub.L ( C.) 1265 1265 1263 1262 1248 1248 1257 1254 1250 13.1 .Math. E+9 T.sub.L 33 32 35 36 50 49 37 39 43 1923 156 .Math. T.sub.L 24 18 37 30 58 52 50 44 62 Young's modulus parameter Y 0.98 0.98 0.98 0.98 0.98 0.98 0.97 0.97 0.97 Liquid phase parameter L 9.5 9.5 9.5 9.5 9.6 9.6 9.6 9.6 9.7 Thermal expansion parameter C 0.80 0.80 0.80 0.80 0.79 0.79 0.79 0.79 0.78 Glass transition point ( C.) 735 735 741 735 741 735 735 729 735 Density (g/cm.sup.3) 2.84 2.85 2.82 2.83 2.80 2.80 2.79 2.80 2.77 Liquid phase viscosity log .sub.L (dPa .Math. s) 2.9 2.9 2.9 2.9 3.0 3.0 3.0 3.0 3.0 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 180 181 182 183 184 185 186 187 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 SrO 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 BaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 0.5 0.5 0.5 0.5 0.5 0.5 0.5 1 TiO.sub.2 1 1 1.5 1.5 1.5 1.5 1.5 0.5 Y.sub.2O.sub.3 1.5 2.5 1 1 2 Gd.sub.2O.sub.3 1 1 2 1 La.sub.2O.sub.3 1 1 2.5 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16.5 16.5 16 16 16 16 16 16.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2.5 2.5 2 2 2 2 2 2.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 9 8 9 8 9 9 8 8 Young's modulus E (GPa) 98 98 98 98 98 98 98 99 Thermal expansion coefficient (ppm/ C.) 3.95 3.84 3.98 4.02 3.87 3.91 3.79 4.05 Liquid phase temperature T.sub.L ( C.) 1249 1232 1279 1279 1256 1253 1233 1255 13.1 .Math. E+9 T.sub.L 44 62 9 33 35 57 44 1923 156 .Math. T.sub.L 58 93 22 17 63 60 99 35 Young's modulus parameter Y 0.97 0.97 0.96 0.96 0.96 0.96 0.96 0.97 Liquid phase parameter L 9.7 9.8 9.7 9.7 9.8 9.8 9.9 9.5 Thermal expansion parameter C 0.78 0.78 0.78 0.78 0.77 0.77 0.77 0.80 Glass transition point ( C.) 729 735 728 728 733 728 733 741 Density (g/cm.sup.3) 2.78 2.73 2.79 2.80 2.74 2.75 2.70 2.84 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.0 3.1 2.8 2.8 3.0 3.0 3.1 3.0 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x Manufacturability determination

TABLE-US-00012 TABLE 12 Example Example Example Example Example Example Example Example Example (mol %) 188 189 190 191 192 193 194 195 196 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 SrO 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 BaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1 1 1 1 1 1 TiO.sub.2 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 1 Y.sub.2O.sub.3 1 1 1.5 1.5 2.5 Gd.sub.2O.sub.3 1 1.5 2.5 1.5 1 La.sub.2O.sub.3 1.5 1 1.5 1 2 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16.5 16.5 16.5 16.5 16.5 16.5 16.5 16.5 16 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 9 9 8 9 9 9 9 8 8 Young's modulus E (GPa) 98 98 98 99 99 99 99 99 98 Thermal expansion coefficient (ppm/ C.) 4.09 4.11 4.14 3.98 4.03 3.94 3.97 3.86 3.97 Liquid phase temperature T.sub.L ( C.) 1252 1251 1251 1233 1229 1233 1231 1218 1234 13.1 .Math. E+9 T.sub.L 47 48 48 67 70 67 69 83 61 1923 156 .Math. T.sub.L 33 31 26 69 65 75 72 103 69 Young's modulus parameter Y 0.97 0.97 0.97 0.98 0.98 0.98 0.98 0.98 0.97 Liquid phase parameter L 9.5 9.5 9.5 9.6 9.6 9.6 9.6 9.7 9.6 Thermal expansion parameter C 0.80 0.80 0.80 0.79 0.79 0.79 0.79 0.78 0.78 Glass transition point ( C.) 735 735 735 741 735 741 735 741 735 Density (g/cm.sup.3) 2.84 2.85 2.86 2.80 2.81 2.78 2.79 2.74 2.79 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.0 3.0 3.0 3.1 3.2 3.1 3.1 3.3 3.1 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 197 198 199 200 201 202 203 204 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 SrO 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 BaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1 1 1 1 1 TiO.sub.2 1 1 1 1 1 1.5 1.5 1.5 Y.sub.2O.sub.3 1 1 2 1.5 Gd.sub.2O.sub.3 1 2 1 1.5 La.sub.2O.sub.3 1 1 1.5 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16 16 16 16 16 15.5 15.5 15.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 2 2 2 2 1.5 1.5 1.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 9 8 9 9 8 8 8 8 Young's modulus E (GPa) 98 98 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 4.01 4.05 3.90 3.93 3.82 3.89 3.95 3.78 Liquid phase temperature T.sub.L ( C.) 1230 1229 1222 1217 1204 1227 1222 1220 13.1 .Math. E+9 T.sub.L 65 65 74 78 92 63 68 71 1923 156 .Math. T.sub.L 67 62 93 92 124 88 85 113 Young's modulus parameter Y 0.97 0.97 0.97 0.97 0.97 0.96 0.96 0.96 Liquid phase parameter L 9.6 9.6 9.7 9.7 9.8 9.8 9.8 10.0 Thermal expansion parameter C 0.78 0.78 0.78 0.78 0.77 0.77 0.77 0.76 Glass transition point ( C.) 728 729 735 728 735 733 728 733 Density (g/cm.sup.3) 2.80 2.80 2.75 2.76 2.71 2.74 2.75 2.68 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.2 3.2 3.2 3.3 3.4 3.2 3.2 3.2 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x Manufacturability determination

TABLE-US-00013 TABLE 13 Example Example Example Example Example Example Example Example Example (mol %) 205 206 207 208 209 210 211 212 213 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 SrO 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 BaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 TiO.sub.2 0.5 0.5 0.5 0.5 0.5 0.5 1 1 1 Y.sub.2O.sub.3 1 1 2 1.5 Gd.sub.2O.sub.3 1 2 1 1.5 La.sub.2O.sub.3 2 1 1 1.5 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16 16 16 16 16 16 15.5 15.5 15.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 2 2 2 2 2 1.5 1.5 1.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 8 9 8 9 9 8 8 8 8 Young's modulus E (GPa) 99 99 99 99 99 99 98 98 98 Thermal expansion coefficient (ppm/ C.) 4.00 4.04 4.07 3.92 3.96 3.84 3.92 3.97 3.80 Liquid phase temperature T.sub.L ( C.) 1257 1253 1252 1235 1231 1221 1237 1232 1223 13.1 .Math. E+9 T.sub.L 45 48 49 67 71 82 61 65 75 1923 156 .Math. T.sub.L 42 40 35 76 75 103 75 72 107 Young's modulus parameter Y 0.97 0.97 0.97 0.98 0.98 0.98 0.97 0.97 0.97 Liquid phase parameter L 9.6 9.6 9.6 9.7 9.7 9.8 9.7 9.7 9.9 Thermal expansion parameter C 0.79 0.79 0.79 0.78 0.78 0.77 0.77 0.77 0.76 Glass transition point ( C.) 741 735 735 741 735 741 735 729 735 Density (g/cm.sup.3) 2.80 2.81 2.81 2.76 2.77 2.72 2.75 2.76 2.69 Liquid phase viscosity log .sub.L (dPa .Math. s) 2.9 3.0 3.0 3.1 3.2 3.2 3.1 3.1 3.2 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 214 215 216 217 218 219 220 221 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.2 0.2 0.2 0.3 0.3 0.3 0.3 0.3 SrO 0.5 0.5 0.5 0.2 0.2 0.2 0.2 0.2 BaO 0.2 0.2 0.2 0.4 0.4 0.4 0.4 0.4 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1.5 1.5 1.5 0.5 0.5 0.5 0.5 0.5 TiO.sub.2 1.5 1.5 1.5 0.5 0.5 0.5 0.5 0.5 Y.sub.2O.sub.3 1 1 1 1 1.5 1.5 Gd.sub.2O.sub.3 1 1 2 1.5 La.sub.2O.sub.3 1 2 1 1.5 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 15 15 15 17 17 17 17 17 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 1 1 1 3 3 3 3 3 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 8 8 8 8 9 8 8 8 Young's modulus E (GPa) 98 98 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 3.84 3.87 3.76 4.03 4.06 4.10 3.99 4.04 Liquid phase temperature T.sub.L ( C.) 1229 1225 1222 1268 1266 1266 1264 1263 13.1 .Math. E+9 T.sub.L 64 68 71 29 31 31 33 34 1923 156 .Math. T.sub.L 95 94 114 26 23 18 37 30 Young's modulus parameter Y 0.96 0.96 0.96 0.97 0.97 0.97 0.98 0.97 Liquid phase parameter L 9.9 9.9 10.0 9.5 9.5 9.5 9.6 9.6 Thermal expansion parameter C 0.76 0.76 0.75 0.80 0.80 0.80 0.80 0.80 Glass transition point ( C.) 733 728 733 741 734 734 741 734 Density (g/cm.sup.3) 2.70 2.71 2.66 2.84 2.85 2.85 2.82 2.83 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.2 3.2 3.2 2.9 2.9 2.9 2.9 2.9 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x Manufacturability determination

TABLE-US-00014 TABLE 14 Example Example Example Example Example Example Example Example Example (mol %) 222 223 224 225 226 227 228 229 230 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SrO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 BaO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 TiO.sub.2 0.5 0.5 1 1 1 1 1 1.5 1.5 Y.sub.2O.sub.3 2 2 1 1 1.5 1.5 2.5 Gd.sub.2O.sub.3 1 1.5 1 1 2 La.sub.2O.sub.3 1 1.5 1 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 17 17 16.5 16.5 16.5 16.5 16.5 16 16 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 3 3 2.5 2.5 2.5 2.5 2.5 2 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 8 8 8 8 8 8 7 8 7 Young's modulus E (GPa) 98 98 98 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 3.95 3.99 3.95 4.00 3.91 3.94 3.83 3.98 4.02 Liquid phase temperature T.sub.L ( C.) 1249 1249 1257 1254 1251 1249 1233 1278 1278 13.1 .Math. E+9 T.sub.L 49 48 35 38 42 43 61 9 9 1923 156 .Math. T.sub.L 58 53 50 44 62 58 93 24 18 Young's modulus parameter Y 0.98 0.98 0.97 0.97 0.97 0.97 0.97 0.96 0.96 Liquid phase parameter L 9.6 9.6 9.7 9.7 9.7 9.7 9.8 9.7 9.7 Thermal expansion parameter C 0.79 0.79 0.79 0.79 0.78 0.78 0.77 0.78 0.78 Glass transition point ( C.) 741 734 734 727 734 727 734 726 726 Density (g/cm.sup.3) 2.80 2.81 2.79 2.80 2.77 2.78 2.73 2.79 2.80 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.0 3.0 2.9 3.0 3.0 3.0 3.1 2.8 2.8 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 231 232 233 234 235 236 237 238 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SrO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 BaO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 0.5 0.5 0.5 1 1 1 1 1 TiO.sub.2 1.5 1.5 1.5 0.5 0.5 0.5 0.5 0.5 Y.sub.2O.sub.3 1 1 2 1 Gd.sub.2O.sub.3 1 1 1.5 2.5 La.sub.2O.sub.3 1 2.5 1.5 1 1.5 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16 16 16 16.5 16.5 16.5 16.5 16.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 2 2 2.5 2.5 2.5 2.5 2.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 8 8 7 7 8 8 7 8 Young's modulus E (GPa) 98 98 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 3.87 3.90 3.79 4.05 4.09 4.10 4.14 3.97 Liquid phase temperature T.sub.L ( C.) 1258 1255 1234 1255 1251 1251 1250 1235 13.1 .Math. E+9 T.sub.L 30 33 54 44 47 48 48 64 1923 156 .Math. T.sub.L 62 59 98 37 34 32 27 68 Young's modulus parameter Y 0.96 0.96 0.96 0.97 0.97 0.97 0.97 0.97 Liquid phase parameter L 9.9 9.9 10.0 9.5 9.5 9.5 9.5 9.6 Thermal expansion parameter C 0.77 0.77 0.76 0.80 0.80 0.80 0.80 0.79 Glass transition point ( C.) 731 726 731 741 734 734 734 741 Density (g/cm.sup.3) 2.74 2.75 2.70 2.84 2.85 2.85 2.86 2.80 Liquid phase viscosity log .sub.L (dPa .Math. s) 2.9 3.0 3.1 3.0 3.0 3.0 3.0 3.1 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x Manufacturability determination

TABLE-US-00015 TABLE 15 Example Example Example Example Example Example Example Example Example (mol %) 239 240 241 242 243 244 245 246 247 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SrO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 BaO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1 1 1 1 1 1 TiO.sub.2 0.5 0.5 0.5 0.5 1 1 1 1 1 Y.sub.2O.sub.3 1 1.5 1.5 2.5 1 1 Gd.sub.2O.sub.3 1.5 1 1 2 1 La.sub.2O.sub.3 1 2 1 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16.5 16.5 16.5 16.5 16 16 16 16 16 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2.5 2.5 2.5 2.5 2 2 2 2 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 8 8 8 7 7 8 7 8 8 Young's modulus E (GPa) 98 99 98 99 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 4.03 3.93 3.97 3.86 3.97 4.01 4.04 3.89 3.93 Liquid phase temperature T.sub.L ( C.) 1231 1235 1233 1219 1233 1229 1228 1223 1219 13.1 .Math. E+9 T.sub.L 68 64 66 81 62 65 66 72 76 1923 156 .Math. T.sub.L 64 74 71 103 71 69 65 93 92 Young's modulus parameter Y 0.97 0.98 0.98 0.98 0.97 0.96 0.96 0.97 0.97 Liquid phase parameter L 9.6 9.7 9.7 9.8 9.7 9.7 9.7 9.8 9.8 Thermal expansion parameter C 0.79 0.79 0.79 0.78 0.78 0.78 0.78 0.77 0.77 Glass transition point ( C.) 734 741 734 741 733 726 726 733 726 Density (g/cm.sup.3) 2.81 2.78 2.79 2.74 2.79 2.80 2.81 2.75 2.76 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.2 3.1 3.1 3.3 3.1 3.2 3.2 3.2 3.3 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 248 249 250 251 252 253 254 255 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SrO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 BaO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1 1.5 1.5 1.5 1.5 TiO.sub.2 1 1.5 1.5 1.5 0.5 0.5 0.5 0.5 Y.sub.2O.sub.3 2 1.5 1 Gd.sub.2O.sub.3 1.5 1 2 La.sub.2O.sub.3 1.5 2 1 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16 15.5 15.5 15.5 16 16 16 16 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 1.5 1.5 1.5 2 2 2 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 7 7 7 7 7 8 7 8 Young's modulus E (GPa) 98 98 98 98 99 99 99 99 Thermal expansion coefficient (ppm/ C.) 3.81 3.89 3.94 3.77 4.00 4.03 4.07 3.92 Liquid phase temperature T.sub.L ( C.) 1205 1227 1222 1222 1254 1250 1249 1234 13.1 .Math. E+9 T.sub.L 90 63 68 69 47 51 51 67 1923 156 .Math. T.sub.L 123 89 86 112 46 44 39 77 Young's modulus parameter Y 0.97 0.96 0.96 0.96 0.97 0.97 0.97 0.97 Liquid phase parameter L 9.9 9.9 9.9 10.0 9.6 9.6 9.6 9.7 Thermal expansion parameter C 0.77 0.77 0.77 0.76 0.79 0.79 0.79 0.78 Glass transition point ( C.) 733 731 725 731 741 734 734 741 Density (g/cm.sup.3) 2.71 2.74 2.75 2.68 2.80 2.81 2.82 2.76 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.4 3.2 3.2 3.2 3.0 3.0 3.0 3.1 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x Manufacturability determination

TABLE-US-00016 TABLE 16 Example Example Example Example Example Example Example Example Example (mol %) 256 257 258 259 260 261 262 263 264 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SrO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.3 BaO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.3 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 0.5 TiO.sub.2 0.5 0.5 1 1 1 1.5 1.5 1.5 0.5 Y.sub.2O.sub.3 1 2 1.5 1 1 Gd.sub.2O.sub.3 1 1.5 1 La.sub.2O.sub.3 1.5 1 2 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16 16 15.5 15.5 15.5 15 15 15 17 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 2 1.5 1.5 1.5 1 1 1 3 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 8 7 7 7 7 7 7 7 8 Young's modulus E (GPa) 99 99 98 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 3.95 3.84 3.92 3.97 3.80 3.83 3.87 3.76 4.03 Liquid phase temperature T.sub.L ( C.) 1230 1219 1233 1228 1221 1226 1222 1222 1263 13.1 .Math. E+9 T.sub.L 71 83 64 69 76 66 71 71 34 1923 156 .Math. T.sub.L 76 105 80 76 109 99 98 115 31 Young's modulus parameter Y 0.97 0.98 0.97 0.97 0.97 0.96 0.96 0.96 0.98 Liquid phase parameter L 9.7 9.8 9.8 9.8 10.0 10.0 10.0 10.1 9.5 Thermal expansion parameter C 0.78 0.77 0.77 0.77 0.76 0.76 0.76 0.75 0.80 Glass transition point ( C.) 734 741 734 727 734 731 726 731 739 Density (g/cm.sup.3) 2.77 2.72 2.75 2.76 2.69 2.70 2.71 2.66 2.84 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.2 3.3 3.1 3.2 3.2 3.2 3.2 3.2 2.9 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 265 266 267 268 269 270 271 272 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SrO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 BaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 TiO.sub.2 0.5 0.5 0.5 0.5 0.5 0.5 1 1 Y.sub.2O.sub.3 1 1 1.5 1.5 2 2 Gd.sub.2O.sub.3 1 2 1.5 1 1 1.5 La.sub.2O.sub.3 1 1.5 1 1.5 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 17 17 17 17 17 17 16.5 16.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 3 3 3 3 3 3 2.5 2.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 9 8 8 8 8 8 8 8 Young's modulus E (GPa) 98 98 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 4.06 4.10 3.99 4.04 3.95 3.99 4.06 4.08 Liquid phase temperature T.sub.L ( C.) 1261 1261 1259 1258 1242 1242 1279 1279 13.1 .Math. E+9 T.sub.L 36 36 39 39 55 55 13 13 1923 156 .Math. T.sub.L 28 23 42 35 64 59 11 8 Young's modulus parameter Y 0.97 0.97 0.98 0.98 0.98 0.98 0.97 0.97 Liquid phase parameter L 9.5 9.5 9.5 9.5 9.6 9.6 9.6 9.6 Thermal expansion parameter C 0.80 0.80 0.80 0.80 0.79 0.79 0.79 0.79 Glass transition point ( C.) 733 733 739 733 739 733 727 727 Density (g/cm.sup.3) 2.84 2.85 2.82 2.83 2.80 2.81 2.84 2.84 Liquid phase viscosity log .sub.L (dPa .Math. s) 2.9 2.9 2.9 2.9 3.1 3.1 2.8 2.8 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x Manufacturability determination

TABLE-US-00017 TABLE 17 Example Example Example Example Example Example Example Example Example (mol %) 273 274 275 276 277 278 279 280 281 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SrO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 BaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 TiO.sub.2 1 1 1 1 1 1 1.5 1.5 1.5 Y.sub.2O.sub.3 1 1 1.5 1.5 2.5 Gd.sub.2O.sub.3 2.5 1.5 1 1 2 La.sub.2O.sub.3 1.5 1 2 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16.5 16.5 16.5 16.5 16.5 16.5 16 16 16 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2.5 2.5 2.5 2.5 2.5 2.5 2 2 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 7 8 8 8 8 7 7 8 7 Young's modulus E (GPa) 98 98 98 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 4.11 3.95 4.00 3.91 3.94 3.83 3.94 3.98 4.02 Liquid phase temperature T.sub.L ( C.) 1279 1253 1250 1247 1245 1227 1276 1273 1273 13.1 .Math. E+9 T.sub.L 13 40 43 47 48 67 12 15 14 1923 156 .Math. T.sub.L 2 54 49 67 63 99 31 29 23 Young's modulus parameter Y 0.97 0.97 0.97 0.97 0.97 0.97 0.96 0.96 0.96 Liquid phase parameter L 9.6 9.7 9.7 9.7 9.7 9.8 9.7 9.7 9.7 Thermal expansion parameter C 0.79 0.79 0.79 0.78 0.78 0.77 0.78 0.78 0.78 Glass transition point ( C.) 727 733 727 733 727 733 731 726 726 Density (g/cm.sup.3) 2.85 2.79 2.80 2.77 2.78 2.73 2.78 2.79 2.80 Liquid phase viscosity log .sub.L (dPa .Math. s) 2.8 3.0 3.0 3.0 3.0 3.2 2.8 2.8 2.8 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 282 283 284 285 286 287 288 289 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SrO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 BaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 0.5 0.5 0.5 1 1 1 1 1 TiO.sub.2 1.5 1.5 1.5 0.5 0.5 0.5 0.5 0.5 Y.sub.2O.sub.3 1 1 2 1 Gd.sub.2O.sub.3 1 1 1.5 2.5 La.sub.2O.sub.3 1 2.5 1.5 1 1.5 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16 16 16 16.5 16.5 16.5 16.5 16.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 2 2 2.5 2.5 2.5 2.5 2.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 8 8 7 7 8 8 7 8 Young's modulus E (GPa) 98 98 98 98 98 98 98 99 Thermal expansion coefficient (ppm/ C.) 3.87 3.90 3.79 4.05 4.09 4.10 4.14 3.97 Liquid phase temperature T.sub.L ( C.) 1253 1250 1227 1251 1248 1247 1246 1231 13.1 .Math. E+9 T.sub.L 36 39 62 48 51 52 52 69 1923 156 .Math. T.sub.L 67 65 105 40 38 36 31 73 Young's modulus parameter Y 0.96 0.96 0.96 0.97 0.97 0.97 0.97 0.98 Liquid phase parameter L 9.8 9.8 9.9 9.5 9.5 9.5 9.5 9.6 Thermal expansion parameter C 0.77 0.77 0.76 0.80 0.80 0.80 0.80 0.79 Glass transition point ( C.) 731 726 731 739 733 733 733 739 Density (g/cm.sup.3) 2.74 2.75 2.70 2.84 2.84 2.85 2.86 2.80 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.0 3.0 3.2 3.0 3.0 3.0 3.0 3.2 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x Manufacturability determination

TABLE-US-00018 TABLE 18 Example Example Example Example Example Example Example Example Example (mol %) 290 291 292 293 294 295 296 297 298 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SrO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 BaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1 1 1 1 1 1 TiO.sub.2 0.5 0.5 0.5 0.5 1 1 1 1 1 Y.sub.2O.sub.3 1 1.5 1.5 2.5 1 1 Gd.sub.2O.sub.3 1.5 1 1 2 1 La.sub.2O.sub.3 1 2 1 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16.5 16.5 16.5 16.5 16 16 16 16 16 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2.5 2.5 2.5 2.5 2 2 2 2 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 8 8 8 7 7 8 7 8 8 Young's modulus E (GPa) 98 99 99 99 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 4.03 3.93 3.97 3.86 3.97 4.01 4.04 3.89 3.93 Liquid phase temperature T.sub.L ( C.) 1226 1231 1228 1214 1230 1226 1225 1219 1215 13.1 .Math. E+9 T.sub.L 73 69 71 87 65 69 69 76 80 1923 156 .Math. T.sub.L 69 79 75 108 74 73 68 96 96 Young's modulus parameter Y 0.98 0.98 0.98 0.98 0.97 0.97 0.97 0.97 0.97 Liquid phase parameter L 9.6 9.7 9.7 9.8 9.7 9.7 9.7 9.8 9.8 Thermal expansion parameter C 0.79 0.79 0.79 0.78 0.78 0.78 0.78 0.78 0.78 Glass transition point ( C.) 733 739 733 739 733 726 726 733 726 Density (g/cm.sup.3) 2.81 2.78 2.79 2.74 2.79 2.80 2.80 2.75 2.76 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.2 3.2 3.2 3.3 3.2 3.2 3.2 3.2 3.3 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 299 300 301 302 303 304 305 306 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SrO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 BaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1.5 1.5 1.5 1.5 1.5 TiO.sub.2 1.5 1.5 1.5 0.5 0.5 0.5 0.5 0.5 Y.sub.2O.sub.3 1.5 1 1 Gd.sub.2O.sub.3 1.5 1 2 1 La.sub.2O.sub.3 1.5 2 1 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 15.5 15.5 15.5 16 16 16 16 16 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 1.5 1.5 1.5 2 2 2 2 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 7 7 7 7 8 7 8 8 Young's modulus E (GPa) 98 98 98 99 99 99 99 99 Thermal expansion coefficient (ppm/ C.) 3.89 3.94 3.77 4.00 4.03 4.07 3.92 3.95 Liquid phase temperature T.sub.L ( C.) 1223 1218 1217 1252 1248 1247 1232 1227 13.1 .Math. E+9 T.sub.L 68 73 74 50 53 54 70 75 1923 156 .Math. T.sub.L 94 90 117 48 46 42 80 79 Young's modulus parameter Y 0.96 0.96 0.96 0.97 0.97 0.97 0.98 0.98 Liquid phase parameter L 9.8 9.8 10.0 9.6 9.6 9.6 9.7 9.7 Thermal expansion parameter C 0.77 0.77 0.76 0.79 0.79 0.79 0.78 0.78 Glass transition point ( C.) 730 725 730 740 733 733 740 733 Density (g/cm.sup.3) 2.74 2.75 2.68 2.80 2.81 2.81 2.76 2.77 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.2 3.3 3.3 3.0 3.0 3.0 3.1 3.2 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x Manufacturability determination

TABLE-US-00019 TABLE 19 Example Example Example Example Example Example Example Example Example (mol %) 307 308 309 310 311 312 313 314 315 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SrO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.4 0.4 BaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.2 0.2 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1.5 1.5 1.5 1.5 1.5 1.5 1.5 0.5 0.5 TiO.sub.2 0.5 1 1 1 1.5 1.5 1.5 0.5 0.5 Y.sub.2O.sub.3 2 1.5 1 1 1 Gd.sub.2O.sub.3 1.5 1 1 La.sub.2O.sub.3 1.5 1 2 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16 15.5 15.5 15.5 15 15 15 17 17 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 1.5 1.5 1.5 1 1 1 3 3 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 7 7 7 7 7 7 7 8 9 Young's modulus E (GPa) 99 98 98 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 3.84 3.91 3.97 3.80 3.83 3.87 3.76 4.03 4.06 Liquid phase temperature T.sub.L ( C.) 1216 1231 1226 1219 1223 1219 1219 1266 1263 13.1 .Math. E+9 T.sub.L 87 66 71 79 70 74 75 32 34 1923 156 .Math. T.sub.L 108 81 78 111 102 100 118 29 26 Young's modulus parameter Y 0.98 0.97 0.97 0.97 0.96 0.96 0.96 0.98 0.98 Liquid phase parameter L 9.8 9.8 9.8 9.9 9.9 9.9 10.0 9.5 9.5 Thermal expansion parameter C 0.77 0.77 0.77 0.76 0.76 0.76 0.75 0.80 0.80 Glass transition point ( C.) 740 734 727 734 731 725 731 741 736 Density (g/cm.sup.3) 2.72 2.75 2.76 2.69 2.70 2.71 2.66 2.83 2.84 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.3 3.2 3.2 3.3 3.2 3.3 3.3 2.9 2.9 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 316 317 318 319 320 321 322 323 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SrO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 BaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 TiO.sub.2 0.5 0.5 0.5 0.5 0.5 1 1 1 Y.sub.2O.sub.3 1 1.5 1.5 2 2 1 1 1.5 Gd.sub.2O.sub.3 2 1.5 1 1.5 La.sub.2O.sub.3 1.5 1 1.5 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 17 17 17 17 17 16.5 16.5 16.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 3 3 3 3 3 2.5 2.5 2.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 8 8 8 8 8 8 8 8 Young's modulus E (GPa) 98 98 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 4.10 3.99 4.04 3.95 3.99 3.95 4.00 3.91 Liquid phase temperature T.sub.L ( C.) 1263 1262 1260 1247 1247 1255 1253 1249 13.1 .Math. E+9 T.sub.L 34 36 37 51 50 38 41 45 1923 156 .Math. T.sub.L 20 39 32 59 54 52 46 64 Young's modulus parameter Y 0.98 0.98 0.98 0.98 0.98 0.97 0.97 0.97 Liquid phase parameter L 9.5 9.5 9.5 9.6 9.6 9.6 9.6 9.7 Thermal expansion parameter C 0.80 0.80 0.80 0.79 0.79 0.79 0.79 0.78 Glass transition point ( C.) 736 741 736 741 736 736 730 736 Density (g/cm.sup.3) 2.85 2.81 2.83 2.80 2.80 2.79 2.80 2.77 Liquid phase viscosity log .sub.L (dPa .Math. s) 2.9 2.9 2.9 3.0 3.0 3.0 3.0 3.0 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x Manufacturability determination

TABLE-US-00020 TABLE 20 Example Example Example Example Example Example Example Example Example (mol %) 324 325 326 327 328 329 330 331 332 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SrO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 BaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 1 TiO.sub.2 1 1 1.5 1.5 1.5 1.5 1.5 1.5 0.5 Y.sub.2O.sub.3 1.5 2.5 1 1 2 Gd.sub.2O.sub.3 1 1 2 1 La.sub.2O.sub.3 2 1 1 2.5 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16.5 16.5 16 16 16 16 16 16 16.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2.5 2.5 2 2 2 2 2 2 2.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 8 7 7 8 7 8 8 7 7 Young's modulus E (GPa) 98 98 98 98 98 98 98 98 99 Thermal expansion coefficient (ppm/ C.) 3.94 3.83 3.94 3.98 4.02 3.87 3.90 3.79 4.05 Liquid phase temperature T.sub.L ( C.) 1248 1231 1279 1276 1276 1255 1252 1232 1253 13.1 .Math. E+9 T.sub.L 46 63 10 12 12 34 37 58 47 1923 156 .Math. T.sub.L 60 94 29 26 20 65 62 100 38 Young's modulus parameter Y 0.97 0.97 0.96 0.96 0.96 0.96 0.96 0.96 0.97 Liquid phase parameter L 9.7 9.8 9.7 9.7 9.7 9.8 9.8 9.9 9.5 Thermal expansion parameter C 0.78 0.78 0.78 0.78 0.78 0.77 0.77 0.76 0.80 Glass transition point ( C.) 730 736 733 729 729 733 729 733 741 Density (g/cm.sup.3) 2.78 2.73 2.78 2.79 2.79 2.74 2.75 2.70 2.83 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.0 3.2 2.8 2.8 2.8 3.0 3.0 3.1 3.0 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 333 334 335 336 337 338 339 340 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SrO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 BaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1 1 1 1 1 TiO.sub.2 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Y.sub.2O.sub.3 1 1 1.5 1.5 2.5 Gd.sub.2O.sub.3 1 1.5 2.5 1.5 1 La.sub.2O.sub.3 1.5 1 1.5 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16.5 16.5 16.5 16.5 16.5 16.5 16.5 16.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 8 8 7 8 8 8 8 7 Young's modulus E (GPa) 99 98 98 99 99 99 99 99 Thermal expansion coefficient (ppm/ C.) 4.09 4.10 4.14 3.97 4.03 3.93 3.97 3.86 Liquid phase temperature T.sub.L ( C.) 1250 1249 1248 1233 1228 1233 1231 1218 13.1 .Math. E+9 T.sub.L 49 50 50 67 71 67 69 83 1923 156 .Math. T.sub.L 36 34 29 70 67 76 73 104 Young's modulus parameter Y 0.97 0.97 0.97 0.98 0.98 0.98 0.98 0.98 Liquid phase parameter L 9.5 9.5 9.5 9.6 9.6 9.6 9.6 9.7 Thermal expansion parameter C 0.80 0.80 0.80 0.79 0.79 0.79 0.79 0.78 Glass transition point ( C.) 736 736 736 741 736 741 736 741 Density (g/cm.sup.3) 2.84 2.85 2.85 2.80 2.81 2.78 2.78 2.74 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.0 3.0 3.0 3.1 3.2 3.1 3.2 3.3 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x Manufacturability determination

TABLE-US-00021 TABLE 21 Example Example Example Example Example Example Example Example Example (mol %) 341 342 343 344 345 346 347 348 349 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SrO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 BaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1 1 1 1 1 1 TiO.sub.2 1 1 1 1 1 1 1.5 1.5 1.5 Y.sub.2O.sub.3 1 1 2 1.5 Gd.sub.2O.sub.3 1 2 1 1.5 La.sub.2O.sub.3 2 1 1 1.5 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16 16 16 16 16 16 15.5 15.5 15.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 2 2 2 2 2 1.5 1.5 1.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 7 8 7 8 8 7 7 7 7 Young's modulus E (GPa) 98 98 98 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 3.97 4.01 4.04 3.89 3.93 3.81 3.89 3.94 3.77 Liquid phase temperature T.sub.L ( C.) 1232 1228 1227 1221 1217 1204 1225 1220 1220 13.1 .Math. E+9 T.sub.L 63 67 68 74 79 93 66 70 72 1923 156 .Math. T.sub.L 72 70 65 94 94 124 91 88 115 Young's modulus parameter Y 0.97 0.97 0.97 0.97 0.97 0.97 0.96 0.96 0.96 Liquid phase parameter L 9.6 9.6 9.6 9.7 9.7 9.9 9.8 9.8 10.0 Thermal expansion parameter C 0.78 0.78 0.78 0.78 0.78 0.77 0.77 0.77 0.76 Glass transition point ( C.) 736 729 730 736 729 736 733 728 733 Density (g/cm.sup.3) 2.79 2.80 2.80 2.75 2.76 2.71 2.74 2.75 2.68 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.1 3.2 3.2 3.2 3.3 3.4 3.2 3.2 3.2 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 350 351 352 353 354 355 356 357 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SrO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 BaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 TiO.sub.2 0.5 0.5 0.5 0.5 0.5 0.5 1 1 Y.sub.2O.sub.3 1 1 2 Gd.sub.2O.sub.3 1 2 1 1.5 La.sub.2O.sub.3 2 1 1 1.5 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16 16 16 16 16 16 15.5 15.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 2 2 2 2 2 1.5 1.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 7 8 7 8 8 7 7 7 Young's modulus E (GPa) 99 99 99 99 99 99 98 98 Thermal expansion coefficient (ppm/ C.) 4.00 4.03 4.07 3.92 3.95 3.84 3.91 3.97 Liquid phase temperature T.sub.L ( C.) 1255 1251 1250 1235 1230 1221 1234 1229 13.1 .Math. E+9 T.sub.L 47 51 51 68 72 82 63 68 1923 156 .Math. T.sub.L 45 43 38 77 76 104 78 75 Young's modulus parameter Y 0.97 0.97 0.97 0.98 0.98 0.98 0.97 0.97 Liquid phase parameter L 9.6 9.6 9.6 9.7 9.7 9.8 9.7 9.7 Thermal expansion parameter C 0.79 0.79 0.79 0.78 0.78 0.77 0.77 0.77 Glass transition point ( C.) 742 736 736 742 736 742 736 730 Density (g/cm.sup.3) 2.80 2.80 2.81 2.76 2.76 2.72 2.75 2.76 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.0 3.0 3.0 3.1 3.2 3.2 3.1 3.2 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x Manufacturability determination

TABLE-US-00022 TABLE 22 Example Example Example Example Example Example Example Example Example (mol %) 358 359 360 361 362 363 364 365 366 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.3 0.3 0.3 0.3 0.4 0.4 0.4 0.4 0.4 SrO 0.4 0.4 0.4 0.4 0.2 0.2 0.2 0.2 0.2 BaO 0.2 0.2 0.2 0.2 0.3 0.3 0.3 0.3 0.3 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1.5 1.5 1.5 1.5 0.5 0.5 0.5 0.5 0.5 TiO.sub.2 1 1.5 1.5 1.5 0.5 0.5 0.5 0.5 0.5 Y.sub.2O.sub.3 1.5 1 1 1 1 1.5 1.5 Gd.sub.2O.sub.3 1 1 2 1.5 La.sub.2O.sub.3 1 2 1 1.5 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 15.5 15 15 15 17 17 17 17 17 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 1.5 1 1 1 3 3 3 3 3 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 7 7 7 7 8 9 8 8 8 Young's modulus E (GPa) 98 98 98 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 3.80 3.83 3.87 3.76 4.02 4.06 4.09 3.98 4.04 Liquid phase temperature T.sub.L ( C.) 1222 1227 1222 1222 1268 1266 1266 1264 1263 13.1 .Math. E+9 T.sub.L 76 67 71 72 29 32 31 34 34 1923 156 .Math. T.sub.L 108 98 97 115 27 24 19 37 30 Young's modulus parameter Y 0.97 0.96 0.96 0.96 0.98 0.97 0.97 0.98 0.98 Liquid phase parameter L 9.9 9.9 9.9 10.0 9.5 9.5 9.5 9.6 9.6 Thermal expansion parameter C 0.76 0.76 0.76 0.75 0.80 0.80 0.80 0.80 0.80 Glass transition point ( C.) 736 733 729 733 741 734 734 741 734 Density (g/cm.sup.3) 2.69 2.70 2.71 2.66 2.84 2.84 2.85 2.82 2.83 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.2 3.2 3.2 3.2 2.9 2.9 2.9 2.9 2.9 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x O x x x x x Manufacturability determination O 6 Example Example Example Example Example Example Example Example (mol %) 367 368 369 370 371 372 373 374 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 SrO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 BaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 TiO.sub.2 0.5 0.5 1 1 1 1 1 1.5 Y.sub.2O.sub.3 2 2 1 1 1.5 1.5 2.5 Gd.sub.2O.sub.3 1 1.5 1 1 La.sub.2O.sub.3 1 1.5 1 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 17 17 16.5 16.5 16.5 16.5 16.5 16 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 3 3 2.5 2.5 2.5 2.5 2.5 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 8 8 8 8 8 8 7 8 Young's modulus E (GPa) 98 98 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 3.95 3.98 3.94 4.00 3.90 3.94 3.83 3.98 Liquid phase temperature T.sub.L ( C.) 1249 1249 1257 1254 1251 1250 1232 1278 13.1 .Math. E+9 T.sub.L 49 49 36 38 43 44 61 10 1923 156 .Math. T.sub.L 59 53 51 45 63 59 94 24 Young's modulus parameter Y 0.98 0.98 0.97 0.97 0.97 0.97 0.97 0.96 Liquid phase parameter L 9.6 9.6 9.7 9.7 9.7 9.7 9.8 9.7 Thermal expansion parameter C 0.79 0.79 0.79 0.79 0.78 0.78 0.77 0.78 Glass transition point ( C.) 741 734 734 727 734 727 734 726 Density (g/cm.sup.3) 2.80 2.80 2.79 2.80 2.77 2.78 2.73 2.79 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.0 3.0 2.9 3.0 3.0 3.0 3.1 2.8 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x Manufacturability determination

TABLE-US-00023 TABLE 23 Example Example Example Example Example Example Example Example Example (mol %) 375 376 377 378 379 380 381 382 383 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 SrO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 BaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 0.5 0.5 0.5 0.5 1 1 1 1 1 TiO.sub.2 1.5 1.5 1.5 1.5 0.5 0.5 0.5 0.5 0.5 Y.sub.2O.sub.3 1 1 2 1 Gd.sub.2O.sub.3 2 1 1 1.5 2.5 La.sub.2O.sub.3 1 2.5 1.5 1 1.5 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16 16 16 16 16.5 16.5 16.5 16.5 16.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 2 2 2 2.5 2.5 2.5 2.5 2.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 7 8 8 7 7 8 8 7 8 Young's modulus E (GPa) 98 98 98 98 99 98 98 98 99 Thermal expansion coefficient (ppm/ C.) 4.01 3.86 3.90 3.78 4.05 4.08 4.10 4.14 3.97 Liquid phase temperature T.sub.L ( C.) 1278 1258 1255 1234 1254 1251 1250 1250 1235 13.1 .Math. E+9 T.sub.L 9 31 34 55 45 48 49 49 65 1923 156 .Math. T.sub.L 19 63 60 99 38 35 33 28 69 Young's modulus parameter Y 0.96 0.96 0.96 0.96 0.97 0.97 0.97 0.97 0.98 Liquid phase parameter L 9.7 9.8 9.8 9.9 9.5 9.5 9.5 9.5 9.6 Thermal expansion parameter C 0.78 0.77 0.77 0.76 0.80 0.80 0.80 0.80 0.79 Glass transition point ( C.) 726 731 726 731 741 734 734 734 741 Density (g/cm.sup.3) 2.79 2.74 2.75 2.70 2.84 2.84 2.85 2.86 2.80 Liquid phase viscosity log .sub.L (dPa .Math. s) 2.8 2.9 3.0 3.1 3.0 3.0 3.0 3.0 3.1 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 384 385 386 387 388 389 390 391 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 SrO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 BaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1 1 1 1 1 TiO.sub.2 0.5 0.5 0.5 0.5 1 1 1 1 Y.sub.2O.sub.3 1 1.5 1.5 2.5 1 Gd.sub.2O.sub.3 1.5 1 1 2 La.sub.2O.sub.3 1 2 1 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16.5 16.5 16.5 16.5 16 16 16 16 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2.5 2.5 2.5 2.5 2 2 2 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 8 8 8 7 7 8 7 8 Young's modulus E (GPa) 99 99 99 99 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 4.02 3.93 3.96 3.85 3.97 4.00 4.04 3.89 Liquid phase temperature T.sub.L ( C.) 1230 1235 1233 1218 1233 1229 1228 1223 13.1 .Math. E+9 T.sub.L 69 65 67 82 63 66 67 73 1923 156 .Math. T.sub.L 65 75 72 104 72 70 66 94 Young's modulus parameter Y 0.98 0.98 0.98 0.98 0.97 0.97 0.97 0.97 Liquid phase parameter L 9.6 9.7 9.7 9.8 9.7 9.7 9.7 9.8 Thermal expansion parameter C 0.79 0.79 0.79 0.78 0.78 0.78 0.78 0.77 Glass transition point ( C.) 734 741 734 741 733 726 727 733 Density (g/cm.sup.3) 2.81 2.78 2.78 2.74 2.79 2.80 2.80 2.75 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.2 3.1 3.1 3.3 3.1 3.2 3.2 3.2 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x Manufacturability determination

TABLE-US-00024 TABLE 24 Example Example Example Example Example Example Example Example Example (mol %) 392 393 394 395 396 397 398 399 400 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 SrO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 BaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1 1 1.5 1.5 1.5 1.5 TiO.sub.2 1 1 1.5 1.5 1.5 0.5 0.5 0.5 0.5 Y.sub.2O.sub.3 1 2 1.5 1 Gd.sub.2O.sub.3 1 1.5 1 2 La.sub.2O.sub.3 1.5 2 1 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16 16 15.5 15.5 15.5 16 16 16 16 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 2 1.5 1.5 1.5 2 2 2 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 8 7 7 7 7 7 8 7 8 Young's modulus E (GPa) 98 98 98 98 98 99 99 99 99 Thermal expansion coefficient (ppm/ C.) 3.92 3.81 3.88 3.94 3.77 3.99 4.03 4.06 3.91 Liquid phase temperature T.sub.L ( C.) 1218 1205 1227 1222 1222 1254 1250 1249 1234 13.1 .Math. E+9 T.sub.L 77 91 64 68 69 48 52 52 68 1923 156 .Math. T.sub.L 93 124 90 87 113 47 45 40 78 Young's modulus parameter Y 0.97 0.97 0.96 0.96 0.96 0.97 0.97 0.97 0.98 Liquid phase parameter L 9.8 9.9 9.8 9.8 10.0 9.6 9.6 9.6 9.7 Thermal expansion parameter C 0.77 0.77 0.77 0.77 0.76 0.79 0.79 0.79 0.78 Glass transition point ( C.) 726 733 731 725 731 741 734 734 741 Density (g/cm.sup.3) 2.76 2.71 2.74 2.75 2.68 2.80 2.80 2.81 2.76 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.3 3.4 3.2 3.2 3.2 3.0 3.0 3.0 3.1 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 401 402 403 404 405 406 407 408 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 SrO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 BaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 TiO.sub.2 0.5 0.5 1 1 1 1.5 1.5 1.5 Y.sub.2O.sub.3 1 2 1.5 1 Gd.sub.2O.sub.3 1 1.5 1 La.sub.2O.sub.3 1.5 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16 16 15.5 15.5 15.5 15 15 15 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 2 1.5 1.5 1.5 1 1 1 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 8 7 7 7 7 7 7 7 Young's modulus E (GPa) 99 99 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 3.95 3.84 3.91 3.96 3.79 3.83 3.87 3.75 Liquid phase temperature T.sub.L ( C.) 1230 1219 1232 1227 1221 1226 1222 1222 13.1 .Math. E+9 T.sub.L 72 84 65 70 77 67 71 72 1923 156 .Math. T.sub.L 77 106 81 77 110 100 99 116 Young's modulus parameter Y 0.98 0.98 0.97 0.97 0.97 0.96 0.96 0.96 Liquid phase parameter L 9.7 9.8 9.8 9.8 9.9 9.9 9.9 10.1 Thermal expansion parameter C 0.78 0.77 0.77 0.77 0.76 0.76 0.76 0.75 Glass transition point ( C.) 734 741 734 727 734 731 726 731 Density (g/cm.sup.3) 2.77 2.72 2.75 2.76 2.69 2.70 2.71 2.66 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.2 3.3 3.1 3.2 3.2 3.2 3.2 3.2 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x Manufacturability determination

TABLE-US-00025 TABLE 25 Example Example Example Example Example Example Example Example Example (mol %) 409 410 411 412 413 414 415 416 417 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 5 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 SrO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 BaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 TiO.sub.2 0.5 0.5 0.5 0.5 0.5 0.5 0.5 1 1 Y.sub.2O.sub.3 1 1 1 1.5 1.5 2 2 1 1 Gd.sub.2O.sub.3 1 2 1.5 1 1.5 La.sub.2O.sub.3 2 1 1.5 1 1.5 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 17 17 17 17 17 17 17 16.5 16.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 3 3 3 3 3 3 3 2.5 2.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 8 9 8 8 8 8 8 8 8 Young's modulus E (GPa) 98 98 98 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 4.02 4.06 4.09 3.98 4.04 3.95 3.98 3.94 4.00 Liquid phase temperature T.sub.L ( C.) 1266 1263 1263 1262 1260 1247 1247 1255 1253 13.1 .Math. E+9 T.sub.L 32 34 34 37 37 51 51 38 41 1923 156 .Math. T.sub.L 30 27 21 40 33 60 55 53 47 Young's modulus parameter Y 0.98 0.98 0.98 0.98 0.98 0.98 0.98 0.97 0.97 Liquid phase parameter L 9.5 9.5 9.5 9.5 9.5 9.6 9.6 9.6 9.6 Thermal expansion parameter C 0.80 0.80 0.80 0.80 0.80 0.79 0.79 0.79 0.79 Glass transition point ( C.) 743 736 736 743 736 743 736 736 730 Density (g/cm.sup.3) 2.83 2.84 2.85 2.81 2.83 2.79 2.80 2.79 2.80 Liquid phase viscosity log .sub.L (dPa .Math. s) 2.9 2.9 2.9 2.9 2.9 3.0 3.0 3.0 3.0 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 418 419 420 421 422 423 424 425 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 SrO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 BaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 TiO.sub.2 1 1 1 1.5 1.5 1.5 1.5 1.5 Y.sub.2O.sub.3 1.5 1.5 2.5 1 1 Gd.sub.2O.sub.3 1 1 2 1 La.sub.2O.sub.3 1 2 1 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16.5 16.5 16.5 16 16 16 16 16 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2.5 2.5 2.5 2 2 2 2 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 8 8 7 7 8 7 8 8 Young's modulus E (GPa) 98 98 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 3.90 3.94 3.83 3.94 3.98 4.01 3.86 3.90 Liquid phase temperature T.sub.L ( C.) 1249 1248 1231 1279 1276 1276 1255 1252 13.1 .Math. E+9 T.sub.L 45 46 63 10 12 12 34 37 1923 156 .Math. T.sub.L 65 61 95 29 27 21 65 63 Young's modulus parameter Y 0.97 0.97 0.97 0.96 0.96 0.96 0.96 0.96 Liquid phase parameter L 9.7 9.7 9.8 9.7 9.7 9.7 9.8 9.8 Thermal expansion parameter C 0.78 0.78 0.77 0.78 0.78 0.78 0.77 0.77 Glass transition point ( C.) 736 729 736 734 728 728 734 728 Density (g/cm.sup.3) 2.77 2.77 2.73 2.78 2.79 2.79 2.74 2.75 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.0 3.0 3.2 2.8 2.8 2.8 3.0 3.0 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x Manufacturability determination

TABLE-US-00026 TABLE 26 Example Example Example Example Example Example Example Example Example (mol %) 426 427 428 429 430 431 432 433 434 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 SrO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 BaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 0.5 1 1 1 1 1 1 1 1 TiO.sub.2 1.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Y.sub.2O.sub.3 2 1 1 1.5 1.5 Gd.sub.2O.sub.3 1 1.5 2.5 1.5 1 La.sub.2O.sub.3 2.5 1.5 1 1.5 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16 16.5 16.5 16.5 16.5 16.5 16.5 16.5 16.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 7 7 8 8 7 8 8 8 8 Young's modulus E (GPa) 98 99 99 99 98 99 99 99 99 Thermal expansion coefficient (ppm/ C.) 3.78 4.05 4.08 4.10 4.13 3.97 4.02 3.93 3.96 Liquid phase temperature T.sub.L ( C.) 1232 1253 1250 1249 1248 1233 1228 1233 1230 13.1 .Math. E+9 T.sub.L 58 47 50 50 51 68 72 68 70 1923 156 .Math. T.sub.L 101 39 37 35 30 72 68 78 74 Young's modulus parameter Y 0.96 0.97 0.97 0.97 0.97 0.98 0.98 0.98 0.98 Liquid phase parameter L 9.9 9.5 9.5 9.5 9.5 9.6 9.6 9.6 9.6 Thermal expansion parameter C 0.76 0.80 0.80 0.80 0.80 0.79 0.79 0.79 0.79 Glass transition point ( C.) 734 743 736 736 736 743 736 743 736 Density (g/cm.sup.3) 2.70 2.83 2.84 2.85 2.85 2.79 2.81 2.77 2.78 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.1 3.0 3.0 3.0 3.0 3.1 3.2 3.1 3.2 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 435 436 437 438 439 440 441 442 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 SrO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 BaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1 1 1 1 1 TiO.sub.2 0.5 1 1 1 1 1 1 1.5 Y.sub.2O.sub.3 2.5 1 1 2 Gd.sub.2O.sub.3 1 2 1 La.sub.2O.sub.3 2 1 1 1.5 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16.5 16 16 16 16 16 16 15.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2.5 2 2 2 2 2 2 1.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 7 7 8 7 8 8 7 7 Young's modulus E (GPa) 99 98 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 3.85 3.96 4.00 4.04 3.89 3.92 3.81 3.88 Liquid phase temperature T.sub.L ( C.) 1217 1232 1228 1227 1221 1216 1203 1225 13.1 .Math. E+9 T.sub.L 84 64 68 68 75 79 93 66 1923 156 .Math. T.sub.L 105 73 71 66 95 95 125 92 Young's modulus parameter Y 0.98 0.97 0.97 0.97 0.97 0.97 0.97 0.96 Liquid phase parameter L 9.7 9.6 9.6 9.6 9.8 9.8 9.9 9.8 Thermal expansion parameter C 0.78 0.78 0.78 0.78 0.78 0.78 0.77 0.77 Glass transition point ( C.) 743 736 729 729 736 729 736 733 Density (g/cm.sup.3) 2.74 2.79 2.79 2.80 2.75 2.75 2.71 2.74 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.3 3.1 3.2 3.2 3.2 3.3 3.4 3.2 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x Manufacturability determination

TABLE-US-00027 TABLE 27 Example Example Example Example Example Example Example Example Example (mol %) 443 444 445 446 447 448 449 450 451 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 SrO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 BaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1.5 1.5 1.5 1.5 1.5 1.5 1.5 TiO.sub.2 1.5 1.5 0.5 0.5 0.5 0.5 0.5 0.5 1 Y.sub.2O.sub.3 1.5 1 1 2 Gd.sub.2O.sub.3 1.5 1 2 1 La.sub.2O.sub.3 2 1 1 1.5 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 15.5 15.5 16 16 16 16 16 16 15.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 1.5 1.5 2 2 2 2 2 2 1.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 7 7 7 8 7 8 8 7 7 Young's modulus E (GPa) 98 98 99 99 99 99 99 99 98 Thermal expansion coefficient (ppm/ C.) 3.94 3.77 3.99 4.03 4.06 3.91 3.95 3.83 3.91 Liquid phase temperature T.sub.L ( C.) 1220 1219 1255 1251 1250 1234 1230 1220 1234 13.1 .Math. E+9 T.sub.L 71 73 48 51 52 68 72 83 64 1923 156 .Math. T.sub.L 89 116 46 44 39 78 77 105 79 Young's modulus parameter Y 0.96 0.96 0.97 0.97 0.97 0.98 0.98 0.98 0.97 Liquid phase parameter L 9.8 10.0 9.6 9.6 9.6 9.7 9.7 9.8 9.8 Thermal expansion parameter C 0.77 0.76 0.79 0.79 0.79 0.78 0.78 0.77 0.77 Glass transition point ( C.) 728 733 743 736 736 743 736 743 736 Density (g/cm.sup.3) 2.75 2.68 2.79 2.80 2.81 2.76 2.76 2.72 2.75 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.2 3.2 3.0 3.0 3.0 3.1 3.2 3.2 3.1 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 452 453 454 455 456 457 458 459 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 SrO 0.3 0.3 0.3 0.3 0.3 0.5 0.5 0.5 BaO 0.2 0.2 0.2 0.2 0.2 0.5 0.5 0.5 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1.5 1.5 1.5 1.5 1.5 0.5 0.5 0.5 TiO.sub.2 1 1 1.5 1.5 1.5 0.5 0.5 0.5 Y.sub.2O.sub.3 1.5 1 1 1 1.5 Gd.sub.2O.sub.3 1.5 1 1.5 La.sub.2O.sub.3 1 1.5 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 15.5 15.5 15 15 15 16.5 16.5 16.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 1.5 1.5 1 1 1 2.5 2.5 2.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.93 0.93 0.93 N 7 7 7 7 7 10 10 10 Young's modulus E (GPa) 98 98 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 3.96 3.79 3.83 3.86 3.75 4.01 4.06 3.97 Liquid phase temperature T.sub.L ( C.) 1229 1222 1227 1222 1222 1263 1261 1259 13.1 .Math. E+9 T.sub.L 68 77 67 71 72 25 27 29 1923 156 .Math. T.sub.L 76 109 99 98 116 34 29 45 Young's modulus parameter Y 0.97 0.97 0.96 0.96 0.96 0.97 0.97 0.97 Liquid phase parameter L 9.8 9.9 9.9 9.9 10.0 9.6 9.6 9.6 Thermal expansion parameter C 0.77 0.76 0.76 0.76 0.75 0.80 0.80 0.79 Glass transition point ( C.) 729 736 734 728 734 736 730 736 Density (g/cm.sup.3) 2.76 2.69 2.70 2.71 2.66 2.80 2.81 2.78 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.2 3.2 3.2 3.2 3.2 2.9 2.9 2.9 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x Manufacturability determination

TABLE-US-00028 TABLE 28 Example Example Example Example Example Example Example Example Example (mol %) 460 461 462 463 464 465 466 467 468 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 SrO 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 BaO 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 0.5 0.5 0.5 0.5 0.5 0.5 0.5 1 1 TiO.sub.2 0.5 0.5 1 1 1 1 1 0.5 0.5 Y.sub.2O.sub.3 1.5 2.5 1 1 2 Gd.sub.2O.sub.3 1 1 2 1 1 La.sub.2O.sub.3 1 1 2 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16.5 16.5 16 16 16 16 16 16 16 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2.5 2.5 2 2 2 2 2 2 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 N 10 9 10 9 10 10 9 9 10 Young's modulus E (GPa) 98 98 97 97 97 97 97 98 98 Thermal expansion coefficient (ppm/ C.) 4.01 3.89 4.04 4.08 3.93 3.96 3.85 4.03 4.07 Liquid phase temperature T.sub.L ( C.) 1258 1241 1279 1279 1253 1250 1228 1251 1247 13.1 .Math. E+9 T.sub.L 30 47 4 3 31 33 56 39 42 1923 156 .Math. T.sub.L 40 74 13 8 57 55 95 43 41 Young's modulus parameter Y 0.97 0.97 0.96 0.96 0.96 0.96 0.96 0.96 0.96 Liquid phase parameter L 9.6 9.7 9.6 9.6 9.7 9.7 9.8 9.6 9.6 Thermal expansion parameter C 0.79 0.78 0.79 0.79 0.78 0.78 0.77 0.79 0.79 Glass transition point ( C.) 730 736 725 725 731 725 731 737 730 Density (g/cm.sup.3) 2.79 2.74 2.80 2.81 2.75 2.76 2.71 2.80 2.81 Liquid phase viscosity log .sub.L (dPa .Math. s) 2.9 3.1 2.8 2.8 3.0 3.0 3.2 3.0 3.0 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 469 470 471 472 473 474 475 476 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 SrO 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 BaO 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1 1 1 1 1.5 TiO.sub.2 0.5 0.5 0.5 0.5 1 1 1 0.5 Y.sub.2O.sub.3 1 1 2 1.5 Gd.sub.2O.sub.3 2 1 1.5 La.sub.2O.sub.3 1 1.5 1.5 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16 16 16 16 15.5 15.5 15.5 15.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 2 2 2 1.5 1.5 1.5 1.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 N 9 10 10 9 9 9 9 9 Young's modulus E (GPa) 98 98 98 98 97 97 97 98 Thermal expansion coefficient (ppm/ C.) 4.10 3.95 3.99 3.88 3.95 4.00 3.83 3.98 Liquid phase temperature T.sub.L ( C.) 1246 1230 1226 1214 1230 1225 1218 1252 13.1 .Math. E+9 T.sub.L 43 60 64 76 56 60 68 40 1923 156 .Math. T.sub.L 37 76 75 104 77 73 107 51 Young's modulus parameter Y 0.96 0.97 0.97 0.97 0.96 0.96 0.96 0.96 Liquid phase parameter L 9.6 9.7 9.7 9.8 9.7 9.7 9.9 9.7 Thermal expansion parameter C 0.79 0.79 0.79 0.78 0.78 0.78 0.77 0.78 Glass transition point ( C.) 731 737 730 737 731 724 731 737 Density (g/cm.sup.3) 2.82 2.76 2.77 2.72 2.75 2.76 2.69 2.76 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.0 3.2 3.2 3.3 3.2 3.2 3.3 3.0 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x Manufacturability determination

TABLE-US-00029 TABLE 29 Example Example Example Example Example Example Example Example Example (mol %) 477 478 479 480 481 482 483 484 485 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.4 0.4 0.4 0.4 0.4 0.5 0.5 0.5 0.5 SrO 0.5 0.5 0.5 0.5 0.5 0.2 0.2 0.2 0.2 BaO 0.5 0.5 0.5 0.5 0.5 0.2 0.2 0.2 0.2 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1.5 1.5 1.5 1.5 1.5 0.5 0.5 0.5 0.5 TiO.sub.2 0.5 0.5 1 1 1 0.5 0.5 0.5 0.5 Y.sub.2O.sub.3 1.5 1 1 1 1 1.5 Gd.sub.2O.sub.3 1.5 1 1 2 La.sub.2O.sub.3 1 2 1 1.5 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 15.5 15.5 15 15 15 17 17 17 17 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 1.5 1.5 1 1 1 3 3 3 3 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.93 0.93 0.93 0.93 0.93 0.96 0.96 0.96 0.96 N 9 9 9 9 9 9 10 9 9 Young's modulus E (GPa) 98 98 98 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 4.03 3.86 3.90 3.93 3.82 4.02 4.05 4.09 3.98 Liquid phase temperature T.sub.L ( C.) 1247 1230 1230 1226 1218 1271 1268 1268 1267 13.1 .Math. E+9 T.sub.L 44 62 57 61 70 28 30 29 32 1923 156 .Math. T.sub.L 47 91 85 84 109 25 22 17 36 Young's modulus parameter Y 0.96 0.97 0.96 0.96 0.96 0.98 0.98 0.98 0.98 Liquid phase parameter L 9.7 9.8 9.8 9.8 9.9 9.5 9.5 9.5 9.5 Thermal expansion parameter C 0.78 0.77 0.77 0.77 0.76 0.80 0.80 0.80 0.80 Glass transition point ( C.) 731 737 731 725 731 744 737 737 744 Density (g/cm.sup.3) 2.77 2.70 2.71 2.72 2.67 2.83 2.84 2.85 2.81 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.0 3.2 3.2 3.2 3.3 2.8 2.9 2.9 2.9 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 486 487 488 489 490 491 492 493 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 SrO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 BaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 TiO.sub.2 0.5 0.5 0.5 1 1 1 1 1 Y.sub.2O.sub.3 1.5 2 2 1 1 1.5 1.5 2.5 Gd.sub.2O.sub.3 1.5 1 1.5 1 La.sub.2O.sub.3 1 1.5 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 17 17 17 16.5 16.5 16.5 16.5 16.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 3 3 3 2.5 2.5 2.5 2.5 2.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 9 9 9 9 9 9 9 8 Young's modulus E (GPa) 98 98 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 4.03 3.94 3.98 3.94 3.99 3.90 3.93 3.82 Liquid phase temperature T.sub.L ( C.) 1265 1254 1254 1260 1257 1254 1252 1237 13.1 .Math. E+9 T.sub.L 33 45 45 34 37 41 42 58 1923 156 .Math. T.sub.L 28 55 49 49 43 61 57 90 Young's modulus parameter Y 0.98 0.98 0.98 0.97 0.97 0.97 0.97 0.97 Liquid phase parameter L 9.5 9.6 9.6 9.7 9.7 9.7 9.7 9.8 Thermal expansion parameter C 0.80 0.79 0.79 0.79 0.79 0.78 0.78 0.77 Glass transition point ( C.) 737 744 737 737 730 737 729 737 Density (g/cm.sup.3) 2.82 2.79 2.80 2.78 2.80 2.76 2.77 2.73 Liquid phase viscosity log .sub.L (dPa .Math. s) 2.9 3.0 3.0 2.9 2.9 3.0 3.0 3.1 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x Manufacturability determination

TABLE-US-00030 TABLE 30 Example Example Example Example Example Example Example Example Example (mol %) 494 495 496 497 498 499 500 501 502 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 SrO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 BaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 0.5 0.5 0.5 1 1 1 1 1 1 TiO.sub.2 1.5 1.5 1.5 0.5 0.5 0.5 0.5 0.5 0.5 Y.sub.2O.sub.3 1 1 2 1 1 Gd.sub.2O.sub.3 1 1 1.5 2.5 1.5 La.sub.2O.sub.3 1 2.5 1.5 1 1.5 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16 16 16 16.5 16.5 16.5 16.5 16.5 16.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 2 2 2.5 2.5 2.5 2.5 2.5 2.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 9 9 8 8 9 9 8 9 9 Young's modulus E (GPa) 98 98 98 99 99 99 98 99 99 Thermal expansion coefficient (ppm/ C.) 3.86 3.89 3.78 4.04 4.08 4.09 4.13 3.96 4.02 Liquid phase temperature T.sub.L ( C.) 1261 1258 1239 1257 1253 1253 1252 1237 1233 13.1 .Math. E+9 T.sub.L 29 32 52 44 46 47 47 64 67 1923 156 .Math. T.sub.L 61 58 95 36 34 32 27 68 64 Young's modulus parameter Y 0.96 0.96 0.96 0.97 0.97 0.97 0.97 0.98 0.98 Liquid phase parameter L 9.8 9.8 9.9 9.5 9.5 9.5 9.5 9.6 9.6 Thermal expansion parameter C 0.77 0.77 0.76 0.80 0.80 0.80 0.80 0.79 0.79 Glass transition point ( C.) 734 728 734 744 737 737 737 744 737 Density (g/cm.sup.3) 2.74 2.74 2.70 2.83 2.84 2.84 2.85 2.79 2.81 Liquid phase viscosity log .sub.L (dPa .Math. s) 2.9 2.9 3.1 3.0 3.0 3.0 3.0 3.1 3.1 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 503 504 505 506 507 508 509 510 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 SrO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 BaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1 1 1 1 1 TiO.sub.2 0.5 0.5 0.5 1 1 1 1 1 Y.sub.2O.sub.3 1.5 1.5 2.5 1 1 Gd.sub.2O.sub.3 1 1 2 1 La.sub.2O.sub.3 1 2 1 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16.5 16.5 16.5 16 16 16 16 16 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2.5 2.5 2.5 2 2 2 2 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 9 9 8 8 9 8 9 9 Young's modulus E (GPa) 99 99 99 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 3.92 3.96 3.85 3.96 4.00 4.03 3.88 3.92 Liquid phase temperature T.sub.L ( C.) 1237 1235 1222 1235 1231 1230 1225 1220 13.1 .Math. E+9 T.sub.L 64 66 79 61 65 65 71 76 1923 156 .Math. T.sub.L 74 70 101 70 69 64 92 91 Young's modulus parameter Y 0.98 0.98 0.98 0.97 0.97 0.97 0.97 0.97 Liquid phase parameter L 9.7 9.7 9.8 9.7 9.7 9.7 9.8 9.8 Thermal expansion parameter C 0.79 0.79 0.78 0.78 0.78 0.78 0.77 0.77 Glass transition point ( C.) 744 737 744 736 729 729 736 729 Density (g/cm.sup.3) 2.77 2.78 2.73 2.78 2.79 2.80 2.75 2.75 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.1 3.1 3.2 3.1 3.2 3.2 3.2 3.2 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x Manufacturability determination

TABLE-US-00031 TABLE 31 Example Example Example Example Example Example Example Example Example (mol %) 511 512 513 514 515 516 517 518 519 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 SrO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 BaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1 1.5 1.5 1.5 1.5 1.5 TiO.sub.2 1 1.5 1.5 1.5 0.5 0.5 0.5 0.5 0.5 Y.sub.2O.sub.3 2 1.5 1 1 Gd.sub.2O.sub.3 1.5 1 2 1 La.sub.2O.sub.3 1.5 2 1 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16 15.5 15.5 15.5 16 16 16 16 16 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 1.5 1.5 1.5 2 2 2 2 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 8 8 8 8 8 9 8 9 9 Young's modulus E (GPa) 98 98 98 98 99 99 99 99 99 Thermal expansion coefficient (ppm/ C.) 3.80 3.88 3.93 3.76 3.99 4.02 4.06 3.91 3.94 Liquid phase temperature T.sub.L ( C.) 1208 1230 1225 1225 1257 1253 1252 1237 1233 13.1 .Math. E+9 T.sub.L 89 62 67 68 46 49 50 66 70 1923 156 .Math. T.sub.L 122 88 85 111 44 43 38 76 75 Young's modulus parameter Y 0.97 0.96 0.96 0.96 0.97 0.97 0.97 0.98 0.98 Liquid phase parameter L 9.9 9.8 9.8 10.0 9.6 9.6 9.6 9.7 9.7 Thermal expansion parameter C 0.77 0.77 0.77 0.76 0.79 0.79 0.79 0.78 0.78 Glass transition point ( C.) 736 733 728 733 744 737 737 744 737 Density (g/cm.sup.3) 2.71 2.74 2.75 2.68 2.79 2.80 2.81 2.75 2.76 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.3 3.2 3.2 3.2 2.9 3.0 3.0 3.1 3.1 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 520 521 522 523 524 525 526 527 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 SrO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.4 BaO 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.5 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1.5 1.5 1.5 1.5 1.5 1.5 1.5 0.5 TiO.sub.2 0.5 1 1 1 1.5 1.5 1.5 0.5 Y.sub.2O.sub.3 2 1.5 1 1 Gd.sub.2O.sub.3 1.5 1 La.sub.2O.sub.3 1.5 1 1.5 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16 15.5 15.5 15.5 15 15 15 16.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 1.5 1.5 1.5 1 1 1 2.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.93 N 8 8 8 8 8 8 8 10 Young's modulus E (GPa) 99 98 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 3.83 3.90 3.96 3.79 3.82 3.86 3.75 4.00 Liquid phase temperature T.sub.L ( C.) 1224 1236 1231 1224 1230 1225 1225 1262 13.1 .Math. E+9 T.sub.L 80 62 67 74 64 68 69 26 1923 156 .Math. T.sub.L 102 78 75 108 97 96 114 36 Young's modulus parameter Y 0.98 0.97 0.97 0.97 0.96 0.96 0.96 0.97 Liquid phase parameter L 9.8 9.8 9.8 9.9 9.9 9.9 10.0 9.6 Thermal expansion parameter C 0.77 0.77 0.77 0.76 0.76 0.76 0.75 0.80 Glass transition point ( C.) 744 737 729 737 734 728 734 737 Density (g/cm.sup.3) 2.72 2.75 2.76 2.69 2.70 2.71 2.66 2.80 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.2 3.1 3.2 3.2 3.2 3.2 3.2 2.9 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x Manufacturability determination

TABLE-US-00032 TABLE 32 Example Example Example Example Example Example Example Example Example (mol %) 528 529 530 531 532 533 534 535 536 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 SrO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 BaO 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 TiO.sub.2 0.5 0.5 0.5 0.5 1 1 1 1 1 Y.sub.2O.sub.3 1 1.5 1.5 2.5 1 1 2 Gd.sub.2O.sub.3 1.5 1 1 2 1 La.sub.2O.sub.3 1 1 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16.5 16.5 16.5 16.5 16 16 16 16 16 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2.5 2.5 2.5 2.5 2 2 2 2 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 N 10 10 10 9 1C 9 10 10 9 Young's modulus E (GPa) 98 98 98 98 97 97 97 97 97 Thermal expansion coefficient (ppm/ C.) 4.06 3.97 4.00 3.89 4.04 4.07 3.92 3.96 3.85 Liquid phase temperature T.sub.L ( C.) 1260 1258 1257 1241 1279 1279 1252 1249 1227 13.1 .Math. E+9 T.sub.L 28 30 31 48 4 4 32 34 57 1923 156 .Math. T.sub.L 30 46 42 75 15 9 59 56 96 Young's modulus parameter Y 0.97 0.97 0.97 0.97 0.96 0.96 0.96 0.96 0.96 Liquid phase parameter L 9.6 9.6 9.6 9.7 9.6 9.6 9.7 9.7 9.9 Thermal expansion parameter C 0.80 0.79 0.79 0.78 0.79 0.79 0.78 0.78 0.77 Glass transition point ( C.) 731 737 731 737 726 726 732 726 732 Density (g/cm.sup.3) 2.81 2.78 2.79 2.74 2.80 2.81 2.75 2.76 2.71 Liquid phase viscosity log .sub.L (dPa .Math. s) 2.9 2.9 2.9 3.1 2.8 2.8 3.0 3.0 3.2 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 537 538 539 540 541 542 543 544 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 SrO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 BaO 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1 1 1 1 1 TiO.sub.2 0.5 0.5 0.5 0.5 0.5 0.5 1 1 Y.sub.2O.sub.3 1 1 2 Gd.sub.2O.sub.3 1 2 1 1.5 La.sub.2O.sub.3 2 1 1 1.5 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16 16 16 16 16 16 15.5 15.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 2 2 2 2 2 1.5 1.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 N 9 10 9 10 10 9 9 9 Young's modulus E (GPa) 98 98 98 98 98 98 97 97 Thermal expansion coefficient (ppm/ C.) 4.03 4.06 4.10 3.95 3.98 3.87 3.95 4.00 Liquid phase temperature T.sub.L ( C.) 1250 1246 1246 1229 1225 1214 1229 1224 13.1 .Math. E+9 T.sub.L 40 43 44 61 65 77 57 61 1923 156 .Math. T.sub.L 45 43 38 78 77 105 78 75 Young's modulus parameter Y 0.96 0.96 0.96 0.97 0.97 0.97 0.96 0.96 Liquid phase parameter L 9.6 9.6 9.6 9.7 9.7 9.8 9.7 9.7 Thermal expansion parameter C 0.79 0.79 0.79 0.79 0.79 0.78 0.78 0.78 Glass transition point ( C.) 737 731 731 737 731 737 731 725 Density (g/cm.sup.3) 2.80 2.81 2.81 2.76 2.77 2.72 2.75 2.76 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.0 3.0 3.0 3.2 3.2 3.3 3.2 3.2 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x Manufacturability determination

TABLE-US-00033 TABLE 33 Example Example Example Example Example Example Example Example Example (mol %) 545 546 547 548 549 550 551 552 553 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 SrO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.5 0.5 BaO 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.4 0.4 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1.5 1.5 1.5 1.5 1.5 1.5 0.5 0.5 TiO.sub.2 1 0.5 0.5 0.5 1 1 1 0.5 0.5 Y.sub.2O.sub.3 1.5 1.5 1 1 1 Gd.sub.2O.sub.3 1.5 1 1.5 La.sub.2O.sub.3 1.5 1 1.5 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 15.5 15.5 15.5 15.5 15 15 15 16.5 16.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 1.5 1.5 1.5 1.5 1 1 1 2.5 2.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 N 9 9 9 9 9 9 9 10 10 Young's modulus E (GPa) 98 98 98 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 3.83 3.97 4.03 3.85 3.89 3.93 3.81 4.00 4.06 Liquid phase temperature T.sub.L ( C.) 1217 1251 1247 1230 1230 1225 1217 1263 1261 13.1 .Math. E+9 T.sub.L 69 41 45 63 58 62 71 25 27 1923 156 .Math. T.sub.L 109 52 49 92 86 85 111 35 29 Young's modulus parameter Y 0.96 0.96 0.96 0.97 0.96 0.96 0.96 0.97 0.97 Liquid phase parameter L 9.9 9.7 9.7 9.8 9.9 9.9 10.0 9.6 9.6 Thermal expansion parameter C 0.77 0.78 0.78 0.77 0.77 0.77 0.76 0.80 0.80 Glass transition point ( C.) 731 737 731 737 732 725 732 737 731 Density (g/cm.sup.3) 2.69 2.76 2.77 2.70 2.71 2.72 2.67 2.80 2.81 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.3 3.0 3.0 3.2 3.2 3.2 3.3 2.9 2.9 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 554 555 556 557 558 559 560 561 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 SrO 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 BaO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 TiO.sub.2 0.5 0.5 0.5 1 1 1 1 1 Y.sub.2O.sub.3 1.5 1.5 2.5 1 1 2 Gd.sub.2O.sub.3 1 1 2 1 La.sub.2O.sub.3 1 1 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 16.5 16.5 16.5 16 16 16 16 16 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2.5 2.5 2.5 2 2 2 2 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 N 10 10 9 10 9 10 10 9 Young's modulus E (GPa) 98 98 98 97 97 97 97 97 Thermal expansion coefficient (ppm/ C.) 3.97 4.00 3.89 4.04 4.07 3.92 3.96 3.85 Liquid phase temperature T.sub.L ( C.) 1259 1258 1241 1279 1279 1253 1250 1228 13.1 .Math. E+9 T.sub.L 30 30 48 4 4 32 34 57 1923 156 .Math. T.sub.L 45 41 75 14 9 58 56 96 Young's modulus parameter Y 0.97 0.97 0.97 0.96 0.96 0.96 0.96 0.96 Liquid phase parameter L 9.6 9.6 9.7 9.6 9.6 9.7 9.7 9.8 Thermal expansion parameter C 0.79 0.79 0.78 0.79 0.79 0.78 0.78 0.77 Glass transition point ( C.) 737 731 737 725 726 732 725 732 Density (g/cm.sup.3) 2.78 2.79 2.74 2.80 2.80 2.75 2.76 2.71 Liquid phase viscosity log .sub.L (dPa .Math. s) 2.9 2.9 3.1 2.8 2.8 3.0 3.0 3.2 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x Manufacturability determination

TABLE-US-00034 TABLE 34 Example Example Example Example Example Example Example Example Example (mol %) 562 563 564 565 566 567 568 569 570 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 20 CaO 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 SrO 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 BaO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 0.5 0.5 0.5 1 1 1 1 1 1 TiO.sub.2 1.5 1.5 1.5 0.5 0.5 0.5 0.5 0.5 0.5 Y.sub.2O.sub.3 1.5 1 1 2 Gd.sub.2O.sub.3 1.5 1 2 1 La.sub.2O.sub.3 1.5 2 1 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 15.5 15.5 15.5 16 16 16 16 16 16 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 1.5 1.5 1.5 2 2 2 2 2 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 N 9 9 9 9 10 9 10 10 9 Young's modulus E (GPa) 97 97 97 98 98 98 98 98 98 Thermal expansion coefficient (ppm/ C.) 3.92 3.97 3.80 4.03 4.06 4.10 3.95 3.98 3.87 Liquid phase temperature T.sub.L ( C.) 1277 1274 1246 1251 1247 1246 1230 1226 1214 13.1 .Math. E+9 T.sub.L 3 5 35 40 43 44 61 65 77 1923 156 .Math. T.sub.L 35 29 84 44 42 37 77 76 105 Young's modulus parameter Y 0.95 0.95 0.95 0.96 0.96 0.96 0.97 0.97 0.97 Liquid phase parameter L 9.8 9.8 9.9 9.6 9.6 9.6 9.7 9.7 9.8 Thermal expansion parameter C 0.78 0.78 0.76 0.79 0.79 0.79 0.79 0.79 0.78 Glass transition point ( C.) 730 725 730 737 731 731 737 731 737 Density (g/cm.sup.3) 2.74 2.75 2.68 2.80 2.80 2.81 2.76 2.77 2.72 Liquid phase viscosity log .sub.L (dPa .Math. s) 2.8 2.8 3.0 3.0 3.0 3.0 3.2 3.2 3.3 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 571 572 573 574 575 576 577 578 SiO.sub.2 52.1 52.1 52.1 52.1 52.1 52.1 52.1 52.1 Al.sub.2O.sub.3 14 14 14 14 14 14 14 14 B.sub.2O.sub.3 9 9 9 9 9 9 9 9 MgO 20 20 20 20 20 20 20 20 CaO 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 SrO 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 BaO 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1 1 1 1.5 1.5 TiO.sub.2 1 1 1 1.5 1.5 1.5 0.5 0.5 Y.sub.2O.sub.3 1.5 1 Gd.sub.2O.sub.3 1.5 1 1.5 La.sub.2O.sub.3 1.5 1 1.5 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 15.5 15.5 15.5 15 15 15 15.5 15.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 1.5 1.5 1.5 1 1 1 1.5 1.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.36 0.36 0.36 0.36 MgO/RO 0.93 0.93 0.93 0.93 0.93 0.93 0.93 0.93 N 9 9 9 9 9 9 9 9 Young's modulus E (GPa) 97 97 98 97 97 97 98 98 Thermal expansion coefficient (ppm/ C.) 3.95 4.00 3.83 3.87 3.90 3.79 3.97 4.02 Liquid phase temperature T.sub.L ( C.) 1230 1225 1218 1222 1218 1217 1252 1247 13.1 .Math. E+9 T.sub.L 56 61 69 60 64 66 41 45 1923 156 .Math. T.sub.L 78 74 108 98 97 115 52 48 Young's modulus parameter Y 0.96 0.96 0.96 0.95 0.95 0.95 0.97 0.96 Liquid phase parameter L 9.7 9.7 9.9 9.9 9.9 10.0 9.7 9.7 Thermal expansion parameter C 0.78 0.78 0.77 0.76 0.76 0.76 0.78 0.78 Glass transition point ( C.) 731 725 731 729 724 729 738 732 Density (g/cm.sup.3) 2.75 2.76 2.69 2.70 2.71 2.66 2.76 2.77 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.2 3.2 3.3 3.2 3.3 3.3 3.0 3.0 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x Manufacturability determination

TABLE-US-00035 TABLE 35 Example Example Example Example Example Example Example Example Example (mol %) 579 580 581 582 583 584 585 586 587 SiO.sub.2 52.1 52.1 52.1 52.1 52.6 52.6 52.6 52.6 52.6 Al.sub.2O.sub.3 14 14 14 14 11.5 11.5 11.5 11.5 12 B.sub.2O.sub.3 9 9 9 9 7 7.5 8 8.5 7 MgO 20 20 20 20 24 23.5 23 22.5 23.5 CaO 0.5 0.5 0.5 0.5 0.3 0.3 0.3 0.3 0.3 SrO 0.5 0.5 0.5 0.5 0.3 0.3 0.3 0.3 0.3 BaO 0.4 0.4 0.4 0.4 0.3 0.3 0.3 0.3 0.3 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1.5 1.5 1.5 1.5 1 1 1 1 1 TiO.sub.2 0.5 1 1 1 1 1 1 1 1 Y.sub.2O.sub.3 1.5 1 2 2 2 2 2 Gd.sub.2O.sub.3 1 La.sub.2O.sub.3 1 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 15.5 15 15 15 13.5 13.5 13.5 13.5 14 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 1.5 1 1 1 2 2 2 2 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.36 0.36 0.36 0.37 0.37 0.36 0.36 0.37 MgO/RO 0.93 0.93 0.93 0.93 0.96 0.96 0.96 0.96 0.96 N 9 9 9 9 7 7 7 7 7 Young's modulus E (GPa) 98 98 98 98 99 99 98 98 99 Thermal expansion coefficient (ppm/ C.) 3.85 3.89 3.93 3.81 4.09 4.07 4.04 4.01 4.05 Liquid phase temperature T.sub.L ( C.) 1230 1230 1226 1218 1200 1202 1200 1199 1200 13.1 .Math. E+9 T.sub.L 63 58 62 71 111 103 98 93 112 1923 156 .Math. T.sub.L 91 86 84 110 85 87 93 98 91 Young's modulus parameter Y 0.97 0.96 0.96 0.96 0.99 0.99 0.98 0.97 0.99 Liquid phase parameter L 9.8 9.8 9.8 9.9 9.6 9.6 9.6 9.5 9.7 Thermal expansion parameter C 0.77 0.77 0.77 0.76 0.82 0.82 0.81 0.81 0.81 Glass transition point ( C.) 738 732 725 732 728 727 727 727 728 Density (g/cm.sup.3) 2.70 2.71 2.72 2.67 2.73 2.72 2.72 2.71 2.73 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.2 3.2 3.2 3.3 3.4 3.4 3.4 3.4 3.4 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x X x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 588 589 590 591 592 593 594 595 SiO.sub.2 52.6 52.6 52.6 52.6 52.6 52.6 52.6 52.6 Al.sub.2O.sub.3 12 12 12 12.5 12.5 12.5 12.5 13 B.sub.2O.sub.3 7.5 8 8.5 7 7.5 8 8.5 7 MgO 23 22.5 22 23 22.5 22 21.5 22.5 CaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SrO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 BaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1 1 1 1 1 TiO.sub.2 1 1 1 1 1 1 1 1 Y.sub.2O.sub.3 2 2 2 2 2 2 2 2 Gd.sub.2O.sub.3 La.sub.2O.sub.3 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 14 14 14 14.5 14.5 14.5 14.5 15 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 2 2 2 2 2 2 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.37 0.36 0.36 0.37 0.37 0.36 0.36 0.37 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 7 7 7 7 7 7 7 7 Young's modulus E (GPa) 99 98 98 100 99 99 98 100 Thermal expansion coefficient (ppm/ C.) 4.02 4.00 3.97 4.01 3.98 3.96 3.93 3.97 Liquid phase temperature T.sub.L ( C.) 1202 1200 1199 1203 1205 1202 1204 1204 13.1 .Math. E+9 T.sub.L 104 100 94 110 101 98 90 110 1923 156 .Math. T.sub.L 93 100 104 95 96 104 106 100 Young's modulus parameter Y 0.99 0.98 0.97 0.99 0.99 0.98 0.97 0.99 Liquid phase parameter L 9.7 9.6 9.6 9.8 9.8 9.7 9.7 9.9 Thermal expansion parameter C 0.81 0.80 0.80 0.80 0.80 0.79 0.79 0.80 Glass transition point ( C.) 727 727 727 729 729 729 729 730 Density (g/cm.sup.3) 2.72 2.72 2.71 2.73 2.72 2.72 2.71 2.73 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.4 3.4 3.4 3.4 3.4 3.4 3.4 3.4 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x Manufacturability determination

TABLE-US-00036 TABLE 36 Example Example Example Example Example Example Example Example Example (mol %) 596 597 598 599 600 601 602 603 604 SiO.sub.2 52.6 52.6 52.6 52.6 52.6 52.6 52.6 53.1 53.1 Al.sub.2O.sub.3 13 13 13 13.5 13.5 13.5 13.5 11.5 11.5 B.sub.2O.sub.3 7.5 8 8.5 7 7.5 8 8.5 7 7.5 MgO 22 21.5 21 22 21.5 21 20.5 23.5 23 CaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SrO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 BaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1 1 1 1 1 1 TiO.sub.2 1 1 1 1 1 1 1 1 1 Y.sub.2O.sub.3 2 2 2 2 2 2 2 2 2 Gd.sub.2O.sub.3 La.sub.2O.sub.3 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 15 15 15 15.5 15.5 15.5 15.5 13.5 13.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 2 2 2 2 2 2 2 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.37 0.36 0.36 0.37 0.37 0.36 0.36 0.37 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 7 7 7 7 7 7 7 7 7 Young's modulus E (GPa) 99 99 98 100 99 99 98 99 99 Thermal expansion coefficient (ppm/ C.) 3.94 3.91 3.89 3.92 3.90 3.87 3.85 4.06 4.03 Liquid phase temperature T.sub.L ( C.) 1206 1204 1203 1205 1207 1203 1201 1201 1203 13.1 .Math. E+9 T.sub.L 102 97 92 110 102 100 96 105 97 1923 156 .Math. T.sub.L 103 108 113 106 108 116 122 89 91 Young's modulus parameter Y 0.99 0.98 0.97 0.99 0.99 0.98 0.97 0.99 0.98 Liquid phase parameter L 9.8 9.8 9.8 10.0 9.9 9.9 9.9 9.7 9.6 Thermal expansion parameter C 0.79 0.79 0.78 0.79 0.78 0.78 0.77 0.81 0.81 Glass transition point ( C.) 730 730 730 732 732 732 732 729 728 Density (g/cm.sup.3) 2.72 2.72 2.71 2.73 2.72 2.72 2.71 2.72 2.72 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.4 3.4 3.4 3.4 3.4 3.4 3.4 3.4 3.4 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 605 606 607 608 609 610 611 612 SiO.sub.2 53.1 53.1 53.1 53.1 53.1 53.1 53.1 53.1 Al.sub.2O.sub.3 11.5 11.5 12 12 12 12 12.5 12.5 B.sub.2O.sub.3 8 8.5 7 7.5 8 8.5 7 7.5 MgO 22.5 22 23 22.5 22 21.5 22.5 22 CaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SrO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 BaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1 1 1 1 1 TiO.sub.2 1 1 1 1 1 1 1 1 Y.sub.2O.sub.3 2 2 2 2 2 2 2 2 Gd.sub.2O.sub.3 La.sub.2O.sub.3 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 13.5 13.5 14 14 14 14 14.5 14.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 2 2 2 2 2 2 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.35 0.37 0.36 0.36 0.35 0.37 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 7 7 7 7 7 7 7 7 Young's modulus E (GPa) 98 98 99 99 98 98 99 99 Thermal expansion coefficient (ppm/ C.) 4.01 3.98 4.02 3.99 3.96 3.94 3.97 3.95 Liquid phase temperature T.sub.L ( C.) 1201 1200 1201 1203 1200 1201 1203 1205 13.1 .Math. E+9 T.sub.L 93 87 106 98 94 88 105 97 1923 156 .Math. T.sub.L 97 102 96 98 104 108 100 102 Young's modulus parameter Y 0.97 0.97 0.99 0.98 0.98 0.97 0.99 0.98 Liquid phase parameter L 9.6 9.6 9.8 9.7 9.7 9.7 9.8 9.8 Thermal expansion parameter C 0.80 0.80 0.81 0.80 0.80 0.79 0.80 0.79 Glass transition point ( C.) 728 728 729 728 728 728 730 730 Density (g/cm.sup.3) 2.71 2.71 2.72 2.72 2.71 2.71 2.72 2.72 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.4 3.4 3.4 3.4 3.4 3.4 3.4 3.4 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x Manufacturability determination

TABLE-US-00037 TABLE 37 Example Example Example Example Example Example Example Example Example (mol %) 613 614 615 616 617 618 619 620 621 SiO.sub.2 53.1 53.1 53.1 53.1 53.1 53.1 53.1 53.1 53.1 Al.sub.2O.sub.3 12.5 12.5 13 13 13 13 13.5 13.5 13.5 B.sub.2O.sub.3 8 8.5 7 7.5 8 8.5 7 7.5 8 MgO 21.5 21 22 21.5 21 20.5 21.5 21 20.5 CaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SrO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 BaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1 1 1 1 1 1 TiO.sub.2 1 1 1 1 1 1 1 1 1 Y.sub.2O.sub.3 2 2 2 2 2 2 2 2 2 Gd.sub.2O.sub.3 La.sub.2O.sub.3 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 14.5 14.5 15 15 15 15 15.5 15.5 15.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 2 2 2 2 2 2 2 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.35 0.37 0.36 0.36 0.35 0.37 0.36 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 7 7 7 7 7 7 7 7 7 Young's modulus E (GPa) 98 98 99 99 98 98 99 99 98 Thermal expansion coefficient (ppm/ C.) 3.92 3.90 3.93 3.91 3.88 3.86 3.89 3.87 3.84 Liquid phase temperature T.sub.L ( C.) 1204 1202 1204 1206 1202 1200 1205 1205 1200 13.1 .Math. E+9 T.sub.L 92 87 106 97 94 90 106 99 98 1923 156 .Math. T.sub.L 107 113 106 107 115 122 111 115 124 Young's modulus parameter Y 0.98 0.97 0.99 0.98 0.98 0.97 0.99 0.98 0.98 Liquid phase parameter L 9.8 9.7 9.9 9.9 9.9 9.8 10.0 10.0 9.9 Thermal expansion parameter C 0.79 0.78 0.79 0.78 0.78 0.77 0.78 0.78 0.77 Glass transition point ( C.) 730 730 731 731 731 731 733 733 733 Density (g/cm.sup.3) 2.71 2.71 2.72 2.72 2.71 2.71 2.72 2.72 2.71 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.4 3.4 3.4 3.4 3.4 3.4 3.4 3.4 3.4 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 622 623 624 625 626 627 628 629 SiO.sub.2 53.1 53.6 53.6 53.6 53.6 53.6 53.6 53.6 Al.sub.2O.sub.3 13.5 11.5 11.5 11.5 11.5 12 12 12 B.sub.2O.sub.3 8.5 7 7.5 8 8.5 7 7.5 8 MgO 20 23 22.5 22 21.5 22.5 22 21.5 CaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SrO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 BaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1 1 1 1 1 TiO.sub.2 1 1 1 1 1 1 1 1 Y.sub.2O.sub.3 2 2 2 2 2 2 2 2 Gd.sub.2O.sub.3 La.sub.2O.sub.3 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 15.5 13.5 13.5 13.5 13.5 14 14 14 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 2 2 2 2 2 2 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.35 0.36 0.36 0.35 0.35 0.36 0.36 0.35 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 7 7 7 7 7 7 7 7 Young's modulus E (GPa) 98 99 98 98 97 99 98 98 Thermal expansion coefficient (ppm/ C.) 3.81 4.02 4.00 3.97 3.95 3.98 3.96 3.93 Liquid phase temperature T.sub.L ( C.) 1200 1201 1203 1200 1200 1201 1202 1200 13.1 .Math. E+9 T.sub.L 92 101 92 88 82 102 94 90 1923 156 .Math. T.sub.L 128 95 97 103 107 101 103 110 Young's modulus parameter Y 0.97 0.98 0.98 0.97 0.96 0.98 0.98 0.97 Liquid phase parameter L 9.9 9.7 9.7 9.6 9.6 9.8 9.8 9.7 Thermal expansion parameter C 0.77 0.81 0.80 0.80 0.79 0.80 0.79 0.79 Glass transition point ( C.) 733 729 728 728 728 729 729 729 Density (g/cm.sup.3) 2.71 2.72 2.71 2.71 2.70 2.72 2.71 2.71 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.4 3.4 3.4 3.4 3.4 3.4 3.4 3.4 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x Manufacturability determination

TABLE-US-00038 TABLE 38 Example Example Example Example Example Example Example Example Example (mol %) 630 631 632 633 634 635 636 637 638 SiO.sub.2 53.6 53.6 53.6 53.6 53.6 53.6 53.6 53.6 53.6 Al.sub.2O.sub.3 12 12.5 12.5 12.5 13 13 13 13 13.5 B.sub.2O.sub.3 8.5 7 7.5 8.5 7 7.5 8 8.5 7 MgO 21 22 21.5 20.5 21.5 21 20.5 20 21 CaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SrO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 BaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1 1 1 1 1 1 TiO.sub.2 1 1 1 1 1 1 1 1 1 Y.sub.2O.sub.3 2 2 2 2 2 2 2 2 2 Gd.sub.2O.sub.3 La.sub.2O.sub.3 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 14 14.5 14.5 14.5 15 15 15 15 15.5 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 2 2 2 2 2 2 2 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.35 0.36 0.36 0.35 0.36 0.36 0.35 0.35 0.36 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 7 7 7 7 7 7 7 7 7 Young's modulus E (GPa) 97 99 98 97 99 98 98 97 99 Thermal expansion coefficient (ppm/ C.) 3.91 3.94 3.91 3.86 3.90 3.87 3.85 3.82 3.86 Liquid phase temperature T.sub.L ( C.) 1198 1203 1207 1199 1204 1205 1200 1200 1203 13.1 .Math. E+9 T.sub.L 85 101 91 85 100 94 92 86 103 1923 156 .Math. T.sub.L 116 105 106 121 110 114 123 127 118 Young's modulus parameter Y 0.96 0.99 0.98 0.96 0.99 0.98 0.97 0.97 0.99 Liquid phase parameter L 9.7 9.9 9.8 9.8 10.0 9.9 9.9 9.9 10.0 Thermal expansion parameter C 0.78 0.79 0.78 0.77 0.78 0.78 0.77 0.77 0.77 Glass transition point ( C.) 729 731 730 730 732 732 732 732 734 Density (g/cm.sup.3) 2.70 2.72 2.71 2.70 2.72 2.71 2.71 2.70 2.72 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.4 3.4 3.4 3.4 3.4 3.4 3.4 3.4 3.4 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 639 640 641 642 643 644 645 646 SiO.sub.2 53.6 53.6 54.1 54.1 54.1 54.1 54.1 54.1 Al.sub.2O.sub.3 13.5 13.5 11.5 11.5 11.5 11.5 12 12 B.sub.2O.sub.3 7.5 8 7 7.5 8 8.5 7 7.5 MgO 20.5 20 22.5 22 21.5 21 22 21.5 CaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SrO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 BaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1 1 1 1 1 TiO.sub.2 1 1 1 1 1 1 1 1 Y.sub.2O.sub.3 2 2 2 2 2 2 2 2 Gd.sub.2O.sub.3 La.sub.2O.sub.3 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 15.5 15.5 13.5 13.5 13.5 13.5 14 14 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 2 2 2 2 2 2 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.35 0.36 0.35 0.35 0.34 0.36 0.35 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 7 7 7 7 7 7 7 7 Young's modulus E (GPa) 99 98 98 98 97 97 98 98 Thermal expansion coefficient (ppm/ C.) 3.83 3.81 3.99 3.96 3.94 3.91 3.95 3.92 Liquid phase temperature T.sub.L ( C.) 1202 1199 1201 1202 1200 1198 1201 1203 13.1 .Math. E+9 T.sub.L 98 94 96 88 84 79 97 89 1923 156 .Math. T.sub.L 123 130 100 102 108 114 107 109 Young's modulus parameter Y 0.98 0.97 0.98 0.97 0.97 0.96 0.98 0.97 Liquid phase parameter L 10.0 10.0 9.7 9.7 9.7 9.6 9.8 9.8 Thermal expansion parameter C 0.77 0.76 0.80 0.79 0.79 0.78 0.79 0.79 Glass transition point ( C.) 733 733 729 729 729 728 729 729 Density (g/cm.sup.3) 2.71 2.71 2.71 2.71 2.70 2.70 2.71 2.71 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.4 3.4 3.4 3.4 3.4 3.4 3.4 3.4 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x Manufacturability determination

TABLE-US-00039 TABLE 39 Example Example Example Example Example Example Example Example Example (mol %) 647 648 649 650 651 652 653 654 655 SiO.sub.2 54.1 54.1 54.1 54.1 54.1 54.1 54.1 54.1 54.1 Al.sub.2O.sub.3 12 12 12.5 12.5 12.5 12.5 13 13 13 B.sub.2O.sub.3 8 8.5 7 7.5 8 8.5 7 7.5 8 MgO 21 20.5 21.5 21 20.5 20 21 20.5 20 CaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SrO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 BaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1 1 1 1 1 1 TiO.sub.2 1 1 1 1 1 1 1 1 1 Y.sub.2O.sub.3 2 2 2 2 2 2 2 2 2 Gd.sub.2O.sub.3 La.sub.2O.sub.3 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 14 14 14.5 14.5 14.5 14.5 15 15 15 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 2 2 2 2 2 2 2 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.35 0.34 0.36 0.35 0.35 0.34 0.36 0.35 0.35 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 7 7 7 7 7 7 7 7 7 Young's modulus E (GPa) 97 97 98 98 97 97 99 98 98 Thermal expansion coefficient (ppm/ C.) 3.90 3.87 3.91 3.88 3.86 3.83 3.86 3.84 3.81 Liquid phase temperature T.sub.L ( C.) 1198 1196 1204 1205 1199 1198 1203 1202 1200 13.1 .Math. E+9 T.sub.L 87 83 95 88 87 81 97 91 88 1923 156 .Math. T.sub.L 117 124 109 113 122 127 117 122 128 Young's modulus parameter Y 0.97 0.96 0.98 0.97 0.97 0.96 0.98 0.98 0.97 Liquid phase parameter L 9.8 9.7 9.9 9.9 9.8 9.8 10.0 10.0 9.9 Thermal expansion parameter C 0.78 0.78 0.78 0.78 0.77 0.77 0.77 0.77 0.76 Glass transition point ( C.) 729 729 731 731 731 730 732 732 732 Density (g/cm.sup.3) 2.70 2.70 2.71 2.71 2.70 2.70 2.71 2.71 2.70 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.4 3.5 3.4 3.4 3.4 3.4 3.4 3.4 3.4 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 656 657 658 659 660 661 662 663 SiO.sub.2 54.1 54.1 54.6 54.6 54.6 54.6 54.6 54.6 Al.sub.2O.sub.3 13.5 13.5 11.5 11.5 11.5 11.5 12 12 B.sub.2O.sub.3 7 7.5 7 7.5 8 8.5 7 7.5 MgO 20.5 20 22 21.5 21 20.5 21.5 21 CaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SrO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 BaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 1 1 1 1 1 1 1 1 TiO.sub.2 1 1 1 1 1 1 1 1 Y.sub.2O.sub.3 2 2 2 2 2 2 2 2 Gd.sub.2O.sub.3 La.sub.2O.sub.3 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 15.5 15.5 13.5 13.5 13.5 13.5 14 14 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 2 2 2 2 2 2 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.36 0.35 0.35 0.35 0.34 0.34 0.35 0.35 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 N 7 7 7 7 7 7 7 7 Young's modulus E (GPa) 99 98 98 97 97 96 98 98 Thermal expansion coefficient (ppm/ C.) 3.82 3.80 3.96 3.93 3.91 3.88 3.91 3.89 Liquid phase temperature T.sub.L ( C.) 1201 1202 1201 1203 1199 1196 1201 1201 13.1 .Math. E+9 T.sub.L 100 93 91 83 81 77 92 86 1923 156 .Math. T.sub.L 126 129 105 107 115 122 111 115 Young's modulus parameter Y 0.98 0.98 0.98 0.97 0.96 0.96 0.98 0.97 Liquid phase parameter L 10.1 10.0 9.8 9.7 9.7 9.7 9.9 9.8 Thermal expansion parameter C 0.77 0.76 0.79 0.79 0.78 0.78 0.78 0.78 Glass transition point ( C.) 734 733 729 729 729 729 729 729 Density (g/cm.sup.3) 2.71 2.71 2.71 2.70 2.70 2.69 2.71 2.70 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.4 3.4 3.4 3.4 3.4 3.5 3.4 3.4 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x x x Manufacturability determination

TABLE-US-00040 TABLE 40 Example Example Example Example Example Example Example Example Example (mol %) 664 665 666 667 668 669 670 671 672 SiO.sub.2 54.6 54.6 54.6 54.6 54.6 54.6 54.6 54.6 53 Al.sub.2O.sub.3 12 12 12.5 12.5 12.5 13 13 13.5 14 B.sub.2O.sub.3 8 8.5 7 7.5 8 7 7.5 7 9.1 MgO 20.5 20 21 20.5 20 20.5 20 20 19 CaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 SrO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 BaO 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 1 ZrO.sub.2 1 1 1 1 1 1 1 1 1 TiO.sub.2 1 1 1 1 1 1 1 1 1 Y.sub.2O.sub.3 2 2 2 2 2 2 2 2 1 Gd.sub.2O.sub.3 La.sub.2O.sub.3 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 14 14 14.5 14.5 14.5 15 15 15.5 15 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 2 2 2 2 2 2 2 2 1 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.34 0.34 0.35 0.35 0.34 0.35 0.35 0.35 0.35 MgO/RO 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.96 0.95 N 7 7 7 7 7 7 7 7 8 Young's modulus E (GPa) 97 97 98 98 97 98 98 98 96 Thermal expansion coefficient (ppm/ C.) 3.86 3.84 3.87 3.85 3.82 3.83 3.81 3.79 3.72 Liquid phase temperature T.sub.L ( C.) 1196 1195 1203 1202 1198 1201 1202 1200 1212 13.1 .Math. E+9 T.sub.L 84 78 92 86 83 94 87 96 52 1923 156 .Math. T.sub.L 124 129 116 121 129 124 128 132 132 Young's modulus parameter Y 0.96 0.96 0.98 0.97 0.96 0.98 0.97 0.98 0.95 Liquid phase parameter L 9.8 9.8 9.9 9.9 9.9 10.0 10.0 10.1 9.8 Thermal expansion parameter C 0.77 0.77 0.78 0.77 0.77 0.77 0.76 0.76 0.75 Glass transition point ( C.) 729 729 731 731 731 732 732 734 733 Density (g/cm.sup.3) 2.70 2.69 2.71 2.70 2.70 2.71 2.70 2.71 2.69 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.4 3.5 3.4 3.4 3.4 3.4 3.4 3.4 3.3 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< 0.8< Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 <1450 T.sub.3 ( C.) <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 <1300 T.sub.4 ( C.) <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 <1200 Deflection determination Deflection determination in high density process x x x x Manufacturability determination Example Example Example Example Example Example Example Example (mol %) 673 674 675 676 677 678 679 680 SiO.sub.2 53 53 53 66.5 68 52.4 50.3 48 Al.sub.2O.sub.3 14 14 14 13.2 13 13.4 17.1 12 B.sub.2O.sub.3 9.1 9.1 9.1 3.8 5 2.2 7 MgO 19 19 19 12.2 6.8 28.7 17.1 22 CaO 0.3 0.3 0.3 5.5 3.8 1 1 SrO 0.3 0.3 0.3 2.6 4.4 1 1 BaO 0.3 0.3 0.3 1 1 Li.sub.2O 1 1 1 Na.sub.2O 1 0.1 1 K.sub.2O 0.2 0.1 1 ZnO 1 1 1 P.sub.2O.sub.5 ZrO.sub.2 1 1 1 0.3 1 1 TiO.sub.2 1 1 1 0.3 1 1 Y.sub.2O.sub.3 1 1 1 1 1 Gd.sub.2O.sub.3 0.9 1 La.sub.2O.sub.3 WO.sub.3 Ta.sub.2O.sub.5 4.2 Al.sub.2O.sub.3 + rare earth oxide 15 15 15 13.2 13 13.4 19 14 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 1 1 1 0 0 0 6.1 2 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) 0.35 0.35 0.35 0.28 0.22 0.42 0.39 0.38 MgO/RO 0.95 0.95 0.95 0.60 0.45 1.00 0.85 0.88 N 8 8 8 5 6 4 14 15 Young's modulus E (GPa) 96 96 98 91 86 100 111 99 Thermal expansion coefficient (ppm/ C.) 3.67 3.78 3.81 3.91 3.49 3.80 4.06 5.20 Liquid phase temperature T.sub.L ( C.) 1207 1205 1207 1312 1192 1325 1295 1175 13.1 .Math. E+9 T.sub.L 66 58 91 106 56 13 168 132 1923 156 .Math. T.sub.L 143 129 122 1 187 5 5 63 Young's modulus parameter Y 0.95 0.95 0.96 0.92 0.85 0.99 1.10 0.98 Liquid phase parameter L 9.9 9.8 9.8 11.1 10.7 9.7 11.0 9.3 Thermal expansion parameter C 0.73 0.83 0.75 0.74 0.70 0.76 0.84 1.04 Glass transition point ( C.) 734 733 731 791 748 755 747 678 Density (g/cm.sup.3) 2.67 2.63 2.64 2.58 2.85 Liquid phase viscosity log .sub.L (dPa .Math. s) 3.4 3.4 3.4 2.8 K.sub.Ic (MPa .Math. m.sup.0.5) 0.8< 0.8< 0.8< 0.9 Transmittance (%) @308 nm, 0.7 mmt 30 30 30 30 30 30 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 80 80 80 80 80 80 T.sub.2 ( C.) <1450 <1450 <1450 1400< 1376 1349 1320 T.sub.3 ( C.) <1300 <1300 <1300 1341 1229 1212 1178 T.sub.4 ( C.) <1200 <1200 <1200 1129 1115 1077 Deflection determination x x Deflection determination in high density process x x x Manufacturability determination x x x

TABLE-US-00041 TABLE 41 (mol %) Example 681 Example 682 SiO.sub.2 64.1 55 Al.sub.2O.sub.3 9.6 15 B.sub.2O.sub.3 5 MgO 14.9 20 CaO 9.9 SrO BaO Li.sub.2O Na.sub.2O K.sub.2O ZnO P.sub.2O.sub.5 ZrO.sub.2 TiO.sub.2 Y.sub.2O.sub.3 1.4 5 Gd.sub.2O.sub.3 La.sub.2O.sub.3 WO.sub.3 Ta.sub.2O.sub.5 Al.sub.2O.sub.3 + rare earth oxide 11 20 Y.sub.2O.sub.3 + Gd.sub.2O.sub.3 + La.sub.2O.sub.3 + 1.4 5 Nd.sub.2O.sub.3 + Ta.sub.2O.sub.5 + Nb.sub.2O.sub.5 (Al.sub.2O.sub.3 + MgO)/(SiO.sub.2 + 0.28 0.37 Al.sub.2O.sub.3 + B.sub.2O.sub.3 + MgO) MgO/RO 0.60 1.00 N 5 5 Young's modulus E (GPa) 93 105 Thermal expansion 4.57 4.00 coefficient (ppm/ C.) Liquid phase temperature T.sub.L ( C.) 1227 1400< 13.1 .Math. E + 9-T.sub.L 0 1923-156 .Math. -T.sub.L 17 Young's modulus parameter Y 0.95 1.04 Liquid phase parameter L 10.7 10.2 Thermal expansion parameter C 0.86 0.79 Glass transition point ( C.) 678 678 Density (g/cm.sup.3) Liquid phase viscosity log .sub.L (dPa .Math. s) K.sub.lc (MPa .Math. m.sup.0.5) Transmittance (%) @308 nm, 0.7 mmt 30 30 Transmittance (%) @1064 nm, 0.7 mmt 80 80 T.sub.2 ( C.) T.sub.3 ( C.) 1324 T.sub.4 ( C.) 1413 Deflection determination X Deflection determination X X in high density process Manufacturability determination X

Example 1

[0106] In Example 1, a glass having the composition shown in Table 1 was produced. In Example 1, a base plate having a diameter of 320 mm and a thickness of 6 mm was manufactured using a melt casting method. Next, a plurality of plates was cut out from the center of the base plate, each plate having a diameter of 300 mm and a thickness of 3 mm. Both surfaces of each plate were polished using cerium oxide as a polishing material to obtain glass having a thickness of 0.7 mm.

[0107] Young's modulus E (GPa) was measured for the glass of Example 1. The Young's modulus was measured by an ultrasonic pulse method defined in JIS R 1602:1995 Testing methods for elastic modulus of fine ceramics. The bulk density of a sample was measured by the Archimedes method, and the longitudinal wave velocity and the transverse wave velocity are measured using an ultrasonic thickness meter 38DL PLUS manufactured by Olympus Corporation to determine a value of the Young's modulus.

[0108] The linear thermal expansion coefficient (ppm/ C.) of the glass of Example 1 was measured. The measurement was performed within a range of 30 C. to 300 C. using a thermal expansion meter (DIL 402 Expedis Supreme) manufactured by NETZSCH Group as a measuring apparatus, and an average thermal expansion coefficient within a range of 50 C. to 200 C. in that measurement range was used as the linear thermal expansion coefficient .

[0109] A liquid phase temperature T.sub.L ( C.) was measured for the glass of Example 1. The liquid phase temperature T.sub.L was measured by placing glass particles that pass through a sieve with a mesh width of 4.0 mm and do not pass through a sieve with a mesh width of 2.3 mm on a platinum dish, and then holding the glass particles in an electric furnace set at a predetermined temperature for one hour to measure the temperature at which crystals are precipitated.

[0110] For the glass of Example 1, the value on the left side of Formulae (1) and (2) described above was calculated.

[0111] For the glass of Example 1, the Young's modulus parameter Y was calculated using Formula (3) described above.

[0112] For the glass of Example 1, the thermal expansion parameter C was calculated using Formula (5) described above.

[0113] For the glass of Example 1, the liquid phase parameter L was calculated using Formula (4) described above.

[0114] The glass transition temperature ( C.) of the glass of Example 1 was measured. The glass transition temperature was measured by obtaining an expansion curve of the glass up to a softening point thereof, as measured by a thermal expansion measuring apparatus.

[0115] For the glass of Example 1, the density (g/cm.sup.3) was measured. The density was measured by the Archimedes method.

[0116] The liquid phase viscosity of the glass of Example 1 was measured. The liquid phase viscosity was measured by measuring a temperature-viscosity curve by an inner cylinder rotation method and calculating the viscosity at the liquid phase temperature.

[0117] The fracture toughness value K.sub.IC (MPa.Math.m.sup.0.5) of the glass of Example 1 was measured. The fracture toughness value K.sub.IC was measured using a pre-crack introduction fracture test method (Single-Edge-Precracked-Beam (SEPB) method) as defined in JIS R1607:2015 Testing methods for fracture toughness of fine ceramics at room temperature.

[0118] For the glass of Example 1, the transmittance for light at a wavelength of 308 nm and the transmittance for light at a wavelength of 1064 nm were measured. The transmittance was measured by measuring a spectral transmittance curve using an ultraviolet-visible spectrophotometer (UH4150 type, manufactured by Hitachi High-Tech Corporation).

[0119] For the glass of Example 1, the melting temperature T.sub.2, the working temperature T.sub.3, and the molding temperature T.sub.4 were measured. The melting temperature T.sub.2, the working temperature T.sub.3, and the molding temperature T.sub.4 were measured by an inner cylinder rotation method.

[0120] The measurement results and the calculation results are shown in Table 1.

Examples 2 to 682

[0121] In Examples 2 to 682, glasses were manufactured in the same manner as in Example 1 except that compositions of the glasses were as shown in Tables 1 to 41. The measurement results and calculation results of the examples are shown in Tables 1 to 41.

Evaluation

[0122] For the glass of each example, the deflection and manufacturability were determined. A deflection evaluation was carried out on the basis of the Bi-Metal warpage calculation defined in the literature S. Timoshenko, Analysis of Bi-Metal Thermostats J. Opt. Soc. Am. 11 (1925) 233. FIG. 2 is a schematic diagram for explaining the deflection evaluation. Here, as illustrated in FIG. 2, when a semiconductor substrate is cooled from a high temperature state of 200 C. to a low temperature of 20 C. in a process of molding a semiconductor substrate with a resin and bonding the semiconductor substrate to a first surface 12 of the glass 10 processed into the shape illustrated in FIG. 1, a warpage amount is defined as a displacement amount in any one of the upward or downward vertical direction at an edge of the glass 10, with the center of a second surface 14 used as the height reference. Specifically, the warpage amount is calculated by Formula (6).

[00010]$\begin{array}{cc}=\frac{6L^2\left({}_2-{}_1\right)\left(T_2-T_1\right){\left(1+m\right)}^2}{8h\left[3{\left(1+m\right)}^2+\left(1+\mathrm{mn}\right)\left\{m^2+{\left(\mathrm{mn}\right)}^{-1}\right\}\right]}& \left(6\right)\end{array}$

[0123] Here, as illustrated in FIG. 2, L is a length in a warpage direction (lateral direction in FIG. 2) of the glass 10, .sub.1 is a linear thermal expansion coefficient of a resin substrate 20, .sub.2 is a linear thermal expansion coefficient of the glass 10, T.sub.2 is a temperature after cooling (here, 20 C.), and T.sub.1 is a temperature before cooling (here, 200 C.). In addition, m is a.sub.1/a.sub.2, h is a.sub.1+a.sub.2, and n is E.sub.1/E.sub.2. Here, a.sub.1 is the thickness of the resin substrate 20, a.sub.2 is the thickness of the glass 10, E.sub.1 is the Young's modulus of the resin substrate 20, and E.sub.2 is the Young's modulus of the glass 10. In the deflection evaluation, the thickness of the resin substrate 20 to be bonded to the glass 10 was assumed to be 0.3 mm and the Young's modulus was assumed to be 31.5 GPa in consideration of mounting a semiconductor. Assuming that the linear thermal expansion coefficient was 4.0 ppm/ C., the warpage amount was calculated when the thickness of the glass 10 was 0.7 mm and the length L was 300 mm. In the determination of deflection, a case where the absolute value of the calculated warpage amount value was less than 0.8 mm was defined as , and a case where the absolute value was 0.8 mm or more was defined as . In addition, the term manufacturability refers to facilitation of manufacturing, and a liquid phase temperature of less than 1280 C. was defined as , a liquid phase temperature of less than 1260 C. was defined as , and a liquid phase temperature of 1280 C. or more was defined as .

[0124] As an optional evaluation, a deflection evaluation in a high density process was also carried out. In the deflection evaluation in the high density process, the resin substrate 20 to be bonded to the glass 10 was assumed to have a thickness of 0.3 mm and a Young's modulus of 31.5 GPa in consideration of mounting silicon at high density. The linear thermal expansion coefficient was assumed to be 3.2 ppm/ C. In the determination of deflection in this high density process, a case where the absolute value of the calculated warpage amount value was less than 1.08 mm was defined as , and a case where the absolute value was 1.08 mm or more was defined as .

[0125] As shown in Tables 1 to 41, in Examples 1 to 675 in which the liquid phase temperature T.sub.L satisfies Formulae (1) and (2) described above, the deflection determination and the manufacturability determination are to , and it can be seen that it is possible to facilitate manufacturing while minimizing deflection. On the other hand, in Examples 676 to 682 which are Comparative Examples, since the liquid phase temperature T.sub.L does not satisfy at least one of Formula (1) or (2) described above, at least one of the manufacturability determination or the deflection determination was , and it can be seen that the manufacturing could not be facilitated.

[0126] Although the embodiments of the present invention have been described above, the embodiments are not limited by the contents of these embodiments. In addition, the above-described constituent elements include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in a so-called equivalent range. Furthermore, the above-described components can be appropriately combined. Furthermore, various omissions, substitutions, or modifications in the constituent elements can be made without departing from the gist of the above-described embodiments.

[0127] According to the present invention, it is possible to facilitate the manufacturing.

[0128] Although the invention has been described with respect to specific embodiments for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the basic teaching herein set forth.