Ion exchangeable alkali aluminosilicate glass compositions having improved mechanical durability

Abstract

A glass composition comprises: 50.0 mol % to 70.0 mol % SiO.sub.2; 10.0 mol % to 25.0 mol % Al.sub.2O.sub.3; 0.0 mol % to 5.0 mol % P.sub.2O.sub.5; 0.0 mol % to 10.0 mol % B.sub.2O.sub.3; 5.0 mol % to 15.0 mol % Li.sub.2O; 1.0 mol % to 15.0 mol % Na.sub.2O; and 0.0 mol % to 1.0 mol % K.sub.2O. The sum of all alkali oxides, R.sub.2O, present in the glass composition may be in the range from greater than or equal to 11.0 mol % to less than or equal to 23.0 mol %. The sum of Al.sub.2O.sub.3 and R.sub.2O present in the glass composition may be in the range from greater than or equal to 26.0 mol % to less than or equal to 40.0 mol %. The glass composition may satisfy the relationship −0.1≤(Al.sub.2O.sub.3—(R.sub.2O+RO))/Li.sub.2O≤0.3.

Claims

1. A glass-based article comprising: a composition comprising a lithium-based aluminosilicate having a non-zero amount of B.sub.2O.sub.3; first and second opposing surfaces defining a thickness (t) of the glass-based article, wherein the thickness of the glass-based article is greater than or equal to 100 μm and less than or equal to 1000 μm; a failure height of greater than or equal to 100 cm as measured according to Drop Test Method on 180 grit sandpaper; and a Knoop Scratch threshold of greater than or equal to 6.0 N and less than or equal to 12.0 N.

2. The glass-based article of claim 1, wherein the thickness of the glass-based article is greater than or equal to 400 μm and less than or equal to 800 μm.

3. The glass-based article of claim 1, wherein the thickness of the glass-based article is greater than or equal to 400 μm and less than or equal to 700 μm.

4. The glass-based article of claim 1, wherein the failure height of the glass-based article is greater than or equal to 150 cm as measured according to Drop Test Method on 180 grit sandpaper.

5. The glass-based article of claim 1, wherein the failure height of the glass-based article is greater than or equal to 180 cm as measured according to Drop Test Method on 180 grit sandpaper.

6. The glass-based article of claim 1, wherein the glass-based article has a Knoop scratch threshold of greater than or equal to 6.0 N and less than or equal to 12.0 N.

7. The glass-based article of claim 1, wherein the glass-based article has a Knoop scratch threshold of greater than or equal to 7.0 N and less than or equal to 12.0 N.

8. The glass-based article of claim 1, wherein the glass-based article has a softening point of greater than or equal to 650° C. and less than or equal to 950° C.

9. The glass-based article of claim 1, wherein the glass-based article has a softening point of greater than or equal to 650° C. and less than or equal to 800° C.

10. The glass-based article of claim 1, wherein the glass-based article has a K.sub.1C fracture toughness as measured by a chevron notch short bar method of greater than or equal to 0.70.

11. The glass-based article of claim 1, wherein the glass-based article has a composition comprising: greater than 0.0 mol % and less than or equal to 5.0 mol % P.sub.2O.sub.5; and greater than 0.0 mol % and less than or equal to 1.0 mol % K.sub.2O.

12. The glass-based article of claim 1, where the glass-based article is a strengthened glass-based article and has a depth of compression greater than or equal to 0.15t.

13. The glass-based article of claim 1, wherein the glass-based article has a composition comprising: greater than or equal to 50.0 mol % and less than or equal to 70.0 mol % SiO.sub.2; greater than or equal to 10.0 mol % and less than or equal to 25.0 mol % Al.sub.2O.sub.3; greater than or equal to 0.0 mol % and less than or equal to 5.0 mol % P.sub.2O.sub.5; greater than 0.0 mol % and less than or equal to 10.0 mol % B.sub.2O.sub.3; greater than or equal to 5.0 mol % and less than or equal to 15.0 mol % Li.sub.2O; greater than or equal to 1.0 mol % and less than or equal to 15.0 mol % Na.sub.2O; and greater than or equal to 0.0 mol % and less than or equal to 1.0 mol % K.sub.2O.

14. The glass-based article of claim 13, wherein R.sub.2O is greater than or equal to 11.0 mol % and less than or equal to 23.0 mol %, wherein R.sub.2O the sum of alkali metal oxides present in the glass-based article in mol %; Al.sub.2O.sub.3+R.sub.2O is greater than or equal to 26.0 mol % and less than or equal to 40.0 mol %; and −0.1≤(Al.sub.2O.sub.3—(R.sub.2O+RO))/Li.sub.2O≤0.3, wherein RO is the sum of alkaline earth metal oxides present in the glass-based article in mol %.

15. The glass-based article of claim 14, wherein R.sub.2O is greater than or equal to 15.0 mol % and less than or equal to 19.0 mol %.

16. The glass-based article of claim 14, wherein Al.sub.2O.sub.3+R.sub.2O is greater than or equal to 28.0 mol % and less than or equal to 36.0 mol %.

17. The glass-based article of claim 14, wherein 0.0≤(Al.sub.2O.sub.3—(R.sub.2O+RO))/Li.sub.2O≤0.1.

18. The glass-based article of claim 12, wherein the strengthened glass-based article has a compressive stress of greater than or equal to 600 MPa.

19. The glass-based article of claim 12, wherein the strengthened glass-based article has a maximum central tension of greater than or equal to 20.0 MPa.

20. The glass-based article of claim 12, wherein the strengthened glass-based article has a depth of layer of greater than or equal to 5.0 μm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a plan view of an exemplary device-drop machine that may be used to conduct the Drop Test Method;

(2) FIG. 2 is a plan view of the machine of FIG. 1, wherein a chuck of the device-drop machine is released, chuck jaws open, and a puck is released;

(3) FIG. 3 is a plan view of the machine of FIG. 1, wherein the falling puck strikes a drop surface;

(4) FIG. 4 is a schematic view of an apparatus that introduces damage to a glass article via impact with an impacting object;

(5) FIG. 5 schematically depicts a cross section of a glass having compressive stress layers on surfaces thereof according to embodiments disclosed and described herein;

(6) FIG. 6A is a plan view of an exemplary electronic device incorporating any of the glass articles disclosed herein;

(7) FIG. 6B is a perspective view of the exemplary electronic device of FIG. 6A;

(8) FIG. 7 is a plot of the failure height of an example glass composition versus a comparative glass composition;

(9) FIG. 8 is another plot of the failure height of an example glass composition versus a comparative glass composition; and

(10) FIG. 9 is a plot of the retained strength of an example glass composition versus a comparative glass composition.

DETAILED DESCRIPTION

(11) Reference will now be made in detail to various embodiments of ion exchangeable alkali aluminosilicate glass compositions that exhibit improved mechanical durability. According to embodiments, a glass composition comprises: 50.0 mol % to 70.0 mol % SiO.sub.2; 10.0 mol % to 25.0 mol % Al.sub.2O.sub.3; 0.0 mol % to 5.0 mol % P.sub.2O.sub.5; 0.0 mol % to 10.0 mol % B.sub.2O.sub.3; 5.0 mol % to 15.0 mol % Li.sub.2O; 1.0 mol % to 15.0 mol % Na.sub.2O; and 0.0 mol % to 1.0 mol % K.sub.2O. The sum of all alkali oxides, R.sub.2O, present in the glass composition may be in the range from greater than or equal to 11.0 mol % to less than or equal to 23.0 mol %. The sum of Al.sub.2O.sub.3 and R.sub.2O present in the glass composition may be in the range from greater than or equal to 26.0 mol % to less than or equal to 40 mol %. The glass composition may satisfy the relationship −0.1≤(Al.sub.2O.sub.3—(R.sub.2O+RO))/Li.sub.2O≤0.3. Various embodiments of glass compositions will be referred to herein with specific references to the appended drawings.

(12) Ranges may be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another embodiment. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

(13) Directional terms as used herein—for example up, down, right, left, front, back, top, bottom—are made only with reference to the figures as drawn and are not intended to imply absolute orientation.

(14) Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order, nor that with any apparatus specific orientations be required. Accordingly, where a method claim does not actually recite an order to be followed by its steps, or that any apparatus claim does not actually recite an order or orientation to individual components, or it is not otherwise specifically stated in the claims or description that the steps are to be limited to a specific order, or that a specific order or orientation to components of an apparatus is not recited, it is in no way intended that an order or orientation be inferred, in any respect. This holds for any possible non-express basis for interpretation, including: matters of logic with respect to arrangement of steps, operational flow, order of components, or orientation of components; plain meaning derived from grammatical organization or punctuation; and the number or type of embodiments described in the specification.

(15) As used herein, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a” component includes aspects having two or more such components, unless the context clearly indicates otherwise.

(16) A “base composition” is a chemical make-up of a substrate prior to any ion exchange (IOX) treatment. That is, the base composition is undoped by any ions from IOX. A composition at the center of a glass-based article that has been IOX treated is typically the same as the base composition when IOX treatment conditions are such that ions supplied for IOX do not diffuse into the center of the substrate. In one or more embodiments, a central composition at the center of the glass article comprises the base composition. The “center” of the glass article may be measured at a thickness of 0.5t and at least a distance of 0.5t from any edge of the glass article.

(17) The term “lithium-based” means that a lithium comprises a substantial portion of the alkali metal oxides present in a glass composition. Without limitation, “lithium-based” includes glass compositions having at least 5.0 mol % Li.sub.2O in the glass composition.

(18) The term “glass-based article” includes a glass or glass ceramic article formed from a glass composition as disclosed and described herein.

(19) The term “substantially free,” when used to describe the concentration and/or absence of a particular constituent component in a glass composition, means that the constituent component is not intentionally added to the glass composition. However, the glass composition may contain traces of the constituent component as a contaminant or tramp in amounts of less than 0.05 mol %. The terms “0 mol %,” “free,” and the like when used to describe the concentration and/or absence of a particular constituent component in a glass-based article, means that the constituent component is not intentionally added to the glass-based article.

(20) In embodiments of the glass compositions described herein, the concentrations of constituent components (e.g., SiO.sub.2, Al.sub.2O.sub.3, and the like) are specified in mole percent (mol %) on an oxide basis, unless otherwise specified.

(21) The term “softening point,” as used herein, refers to the temperature at which the viscosity of the glass composition is 1×10.sup.7.6 poise. The softening point was determined using the parallel plate viscosity method of ASTM C1351M-96(2012).

(22) The term “annealing point,” as used herein, refers to the temperature at which the viscosity of the glass composition is 1×10.sup.13 poise.

(23) The term “strain point,” as used herein, refers to the temperature at which the viscosity of the glass composition is 1×10.sup.14.68 poise.

(24) The term “CTE,” as used herein, refers to the coefficient of thermal expansion of the glass composition over a temperature range from about 20° C. to about 300° C., unless otherwise specified.

(25) The term “liquidus viscosity,” as used herein, refers to the viscosity of the glass at the onset of devitrification (i.e., at the liquidus temperature as determined with the gradient furnace method according to ASTM C829-81).

(26) The elastic modulus (also referred to as Young's modulus) of the glass is provided in units of gigapascals (GPa). The elastic modulus of the glass is determined by resonant ultrasound spectroscopy on bulk samples of each glass composition.

(27) Density is measured by the buoyancy method of ASTM C693-93(2013).

(28) Glass compositions according to embodiments have a high fracture toughness. Without being bound by any particular theory, the high fracture toughness may impart improved drop performance to the glass compositions. The fracture toughness refers to the K.sub.1C value, and is measured by the chevron notched short bar method. The chevron notched short bar (CNSB) method utilized to measure the K.sub.1C value is disclosed in Reddy, K. P. R. et al, “Fracture Toughness Measurement of Glass and Ceramic Materials Using Chevron-Notched Specimens,” J. Am. Ceram. Soc., 71 [6], C-310-C-313 (1988) except that Y*.sub.m is calculated using equation 5 of Bubsey, R. T. et al., “Closed-Form Expressions for Crack-Mouth Displacement and Stress Intensity Factors for Chevron-Notched Short Bar and Short Rod Specimens Based on Experimental Compliance Measurements,” NASA Technical Memorandum 83796, pp. 1-30 (October 1992). Fracture toughness is measured on a non-strengthened glass article, such as measuring the K.sub.1C value prior to ion exchange (IOX) treatment of the glass article, thereby representing a feature of a glass substrate prior to IOX. The fracture toughness test methods described herein are not suitable for glasses that have been exposed to IOX treatment. The measurements on corresponding underlying glass substrates (without IOX treatment), nonetheless, provide valuable information about the IOX'd glass properties. Accordingly, the fracture toughness of an IOX'd article is measured on an otherwise identical article that has not been IOX'd. Unless otherwise specified, the CSNB method is used to measure fracture toughness values described herein.

(29) The term “single ion exchange process,” as used herein, refers to a process in which the glass composition is exposed to a single ion exchange solution, such as a KNO.sub.3 or NaNO.sub.3 molten salt bath.

(30) The term “double ion exchange process,” as used herein, refers to a process in which the glass composition is exposed to a first ion exchange solution and a second ion exchange solution.

(31) The term “multiple ion exchange process,” as used herein, refers to a process in which the glass composition is exposed to three or more ion exchange solutions.

(32) The term “depth of compression” (DOC), as used herein, refers to the depth at which the stress crosses from a positive (compressive) stress to a negative (tensile) stress and thus exhibits a stress value of zero.

(33) The term “depth of layer” (DOL), as used herein, refers to the depth within a glass-based article (i.e., the distance from a surface of the glass-based article to its interior region) at which an ion of a metal oxide or alkali metal oxide (e.g., the metal ion or alkali metal ion) diffuses into the glass-based article where the concentration of the ion reaches a minimum value, as determined by Glow Discharge—Optical Emission Spectroscopy (GD-OES)). Unless otherwise specified, the DOL is given as the depth of exchange of the slowest-diffusing ion introduced by an ion exchange (IOX) process.

(34) A non-zero metal oxide concentration that varies from the first surface to a depth of layer (DOL) with respect to the metal oxide or that varies along at least a substantial portion of the article thickness (t) indicates that a stress has been generated in the article as a result of ion exchange. The variation in metal oxide concentration may be referred to herein as a metal oxide concentration gradient. The metal oxide that is non-zero in concentration and varies from the first surface to a DOL or along a portion of the thickness may be described as generating a stress in the glass-based article. The concentration gradient or variation of metal oxides is created by chemically strengthening a glass-based substrate in which a plurality of first metal ions in the glass-based substrate is exchanged with a plurality of second metal ions.

(35) According to the convention normally used in the art, compression or compressive stress is expressed as a negative (<0) stress and tension or tensile stress is expressed as a positive (>0) stress. Throughout this description, however, CS is expressed as a positive or absolute value—i.e., as recited herein, CS=|CS|. The compressive stress (CS) has a maximum at or near the surface of the glass, and the CS varies with distance d from the surface according to a function.

(36) Compressive stress (CS) and depth of layer (DOL) are measured by surface stress meter (FSM) using commercially available instruments such as the FSM-6000, manufactured by Orihara Industrial Co., Ltd. (Japan). Surface stress measurements rely upon the accurate measurement of the stress optical coefficient (SOC), which is related to the birefringence of the glass. SOC in turn is measured according to Procedure C (Glass Disc Method) described in ASTM standard C770-16, entitled “Standard Test Method for Measurement of Glass Stress-Optical Coefficient,” the contents of which are incorporated herein by reference in their entirety.

(37) The maximum central tension (CT) or peak tension (PT) and stress retention values are measured using a scattered light polariscope (SCALP) technique known in the art. The Refracted near-field (RNF) method or SCALP may be used to measure the stress profile and the depth of compression (DOC). When the RNF method is utilized to measure the stress profile, the maximum CT value provided by SCALP is utilized in the RNF method. In particular, the stress profile measured by RNF is force balanced and calibrated to the maximum CT value provided by a SCALP measurement. The RNF method is described in U.S. Pat. No. 8,854,623, entitled “Systems and methods for measuring a profile characteristic of a glass sample”, which is incorporated herein by reference in its entirety. In particular, the RNF method includes placing the glass article adjacent to a reference block, generating a polarization-switched light beam that is switched between orthogonal polarizations at a rate of from 1 Hz to 50 Hz, measuring an amount of power in the polarization-switched light beam and generating a polarization-switched reference signal, wherein the measured amounts of power in each of the orthogonal polarizations are within 50% of each other. The method further includes transmitting the polarization-switched light beam through the glass sample and reference block for different depths into the glass sample, then relaying the transmitted polarization-switched light beam to a signal photodetector using a relay optical system, with the signal photodetector generating a polarization-switched detector signal. The method also includes dividing the detector signal by the reference signal to form a normalized detector signal and determining the profile characteristic of the glass sample from the normalized detector signal.

(38) The term, “Knoop Scratch threshold,” as used herein, refers to the onset of lateral cracking (in 3 or more of 5 scratch events). A series of increasing constant-load scratches (3 minimum per load, but more per load could be used to increase confidence level) are performed to identify the Knoop Scratch threshold. In Knoop Scratch threshold testing, for each load, samples of the glass substrates and/or articles were scratched with a Knoop indentor over a length of 10 mm. The following 3 failure modes are used to determine the Knoop Scratch threshold: 1) sustained lateral surface cracks that are more than two times the width of the groove, 2) damage is contained within the groove, but there are lateral surface cracks that are less than two times the width of groove and there is damage visible by naked eye, or 3) the presence of large subsurface lateral cracks which are greater than two times the width of the groove and/or there is a median crack at the vertex of the scratch. The Knoop Scratch threshold is then the highest load at which none of the three above failures occur in 3 or more of 5 events.

(39) The term “failure height,” as used herein, refers to the lowest height from which a device including a glass article can be dropped and the glass article fails (i.e., cracks). The Drop Test Method is used to determine the failure height on a device. The Drop Test Method involves performing face-drop testing on a puck with a glass article attached thereto. The glass article is attached to the puck with Tesa® 61385 double sided adhesive tape to hold the glass article to the puck during the drop test described herein below. The glass article to be tested has a thickness similar or equal to the thickness that will be used in a given hand-held consumer electronic device, such as 0.5 mm or 0.6 mm. A puck refers to a structure meant to mimic the size, shape, and weight distribution of a given device, such as a cell phone. Hereinafter, the term “puck,” refers to a structure that has a weight of 126.0 grams, a length of 133.1 mm, a width of 68.2 mm, and a height of 9.4 mm. In embodiments, the puck has the dimensions and weight similar to a handheld electronic device.

(40) An exemplary device-drop machine that may be used to conduct the Drop Test Method is shown as reference number 10 in FIG. 1. The device-drop machine 10 includes a chuck 12 having chuck jaws 14. The puck 16 is staged in the chuck jaws 14 with the glass article attached thereto and facing downward. The chuck 12 is ready to fall from, for example, an electro-magnetic chuck lifter. Referring now to FIG. 2, the chuck 12 is released and during its fall, the chuck jaws 14 are triggered to open by, for example, a proximity sensor. As the chuck jaws 14 open, the puck 16 is released. Referring now to FIG. 3, the falling puck 16 strikes a drop surface 18. The drop surface 18 may be sandpaper, such as 180 grit sandpaper, positioned on a steel plate. If the glass article attached to the puck survives the fall (i.e., does not crack), the chuck 12 is set at an increased height and the test is repeated. The failure height is then the lowest height from which the puck including the glass article is dropped and the glass composition fails. A single glass article is tested at multiple heights, such as at 22 cm, 30 cm, 40 cm, 50 cm, 60 cm, and increments of 10 centimeters until the glass article fails by showing damage. The sandpaper is replaced upon failure of the glass. Unless otherwise indicated 180 grit sandpaper is used herein.

(41) The term “retained strength,” as used herein, refers to the strength of a glass article after damage introduction by an impact force when the article is bent to impart tensile tress. Damage is introduced according to the method described in U.S. Patent Publication No. 2019/0072469 A1, which is incorporated herein by reference. For example, an apparatus for impact testing a glass article is shown as reference number 1100 in FIG. 4. The apparatus 1100 includes a pendulum 1102 including a bob 1104 attached to a pivot 1106. The term “bob” on a pendulum, as used herein, is a weight suspended from and connected to a pivot by an arm. Thus, the bob 1104 shown is connected to the pivot 1106 by an arm 1108. The bob 1104 includes a base 1110 for receiving a glass article, and the glass article is affixed to the base. The apparatus 1100 further includes an impacting object 1140 positioned such that when the bob 1104 is released from a position at an angle greater than zero from the equilibrium position, the surface of the bob 1104 contacts the impacting object 1140. The impacting object includes an abrasive sheet having an abrasive surface to be placed in contact with the outer surface of the glass article. The abrasive sheet may comprise sandpaper, which may have a grit size in the range of 30 grit to 1000 grit, or 100 grit to 300 grit, for example 80 grit, 120 grit, 180 grit, and 1000 grit sandpaper). Unless otherwise indicated 180 grit sandpaper was used herein.

(42) For purposes of this disclosure, the impacting object was in the form of a 6 mm diameter disk of 80 grit, 120 grit, or 180 grit sandpaper affixed to the apparatus. A glass article having a thickness of approximately 600.0 μm was affixed to the bob. For each impact, a fresh sandpaper disk was used. Damage on the glass article was done at approximately 500.0 N impact force by pulling the swing of the arm of the apparatus to approximately a 90° angle. Approximately 10 samples of each glass article were impacted.

(43) Twelve hours or more after the damage introduction, the glass articles were fractured in four-point bending (4PB). The damaged glass article was placed on support rods (support span) with the damaged site on the bottom (i.e., on the tension side) and between the load roads (loading span). For purposes of this disclosure, the loading span was 18 mm and the support span was 36 mm. The radius of curvature of load and support rods was 3.2 mm. Loading was done at a constant displacement rate of 5 mm/min using a screw-driven testing machine (Instron, Norwood, Mass., USA) until failure of the glass. The 4PB tests were performed at a temperature of 22° C.±2° C. and at a relative humidity (RH) of 50%±5%.

(44) The applied fracture stress (or the applied stress to failure) σ.sub.app in four-point bending (4PB) was calculated from the equation,

(45) $\begin{array}{cc}{\sigma }_{\mathrm{app}}=\frac{1}{\left(1-v^2\right)}\frac{3P\left(L-a\right)}{2{\mathrm{bh}}^2}& \left(1\right)\end{array}$

(46) where, P is the maximum load to failure, L (=36 mm) is the distance between support rods (support span), a (=18 mm) is the distance between the loading rods (loading span), b is the width of the glass plate, h is the thickness of the glass plate and ν is the Poisson's Ratio of the glass composition. The term (1/(1−ν.sup.2)) in Eq. (1) considers the stiffening effect of a plate. In four-point bending, stress is constant under the loading span and thus, the damaged site is under mode I uniaxial tensile stress loading. The stressing rate of the 4-point bend testing for the specimens was estimated to be between 15 to 17 MPa per sec. The retained strength of the glass composition is the highest applied fracture stress at which failure does not occur.

(47) Alkali aluminosilicate glasses have good ion exchangeability. Chemical strengthening processes have been used to achieve high strength and high toughness properties in alkali aluminosilicate glasses. Sodium aluminosilicate glasses are highly ion exchangeable glasses with high glass formability and quality. The substitution of Al.sub.2O.sub.3 into the silicate glass network increases the interdiffusivity of monovalent cations during ion exchange. By chemical strengthening in a molten salt bath (e.g., KNO.sub.3 and/or NaNO.sub.3), glasses with high strength, high toughness, and high indentation cracking resistance may be achieved.

(48) Therefore, alkali aluminosilicate glasses with good physical properties, chemical durability, and ion exchangeability have drawn attention for use as cover glass. In particular, lithium containing aluminosilicate glasses, which have lower annealing and softening temperature, lower CTE values, and fast ion exchangeability are provided herein. Through different ion exchange processes, greater CT, DOC, and CS may be achieved. However, the addition of lithium in the alkali aluminosilicate glass may reduce the melting point, softening point, or liquidus viscosity of the glass.

(49) Drawing processes for forming glass articles, such as, for example, glass sheets, are desirable because they allow a thin glass article to be formed with few defects. It was previously thought that glass compositions were required to have relatively high liquidus viscosities—such as a liquidus viscosity greater than 1000 kP, greater than 1100 kP, or greater than 1200 kP—to be formed by a drawing process, such as, for example, fusion drawing or slot drawing. However, developments in drawing processes allow glasses with lower liquidus viscosities to be used in drawing processes. Thus, glasses used in drawing processes may include more lithia than previously thought, and may include more glass network forming components, such as, for example, SiO.sub.2, Al.sub.2O.sub.3, and B.sub.2O.sub.3. Accordingly, a balance of the various glass components that allows the glass to realize the benefits of adding lithium and glass network formers to the glass composition, but that does not negatively impact the glass composition are provided herein.

(50) In particular, the glass compositions provided herein may include more Li.sub.2O, Al.sub.2O.sub.3, B.sub.2O.sub.3, and MgO and less P.sub.2O.sub.5 and K.sub.2O than conventional glass compositions. The glass compositions provided herein may also include a relatively small amounts of TiO.sub.2. Li.sub.2O, Al.sub.2O.sub.3, B.sub.2O.sub.3, and MgO may have high field strength, which may increase the bonding strength and, thus, the fracture toughness of the glass composition. P.sub.2O.sub.5 and K.sub.2O may have the opposite effect. Such a combination of changing elements may result in lowered softening point. Moreover, the combination of changing elements of the glass compositions provided herein may result in improved fracture toughness and ion exchange properties (e.g., higher CS and higher DOC), which may lead to improved drop test performance.

(51) In embodiments of the alkali aluminosilicate glass compositions disclosed herein, SiO.sub.2 is the largest constituent and, as such, SiO.sub.2 is the primary constituent of the glass network formed from the glass composition. Pure SiO.sub.2 has a relatively low CTE and is alkali free. However, pure SiO.sub.2 has a high melting point. Accordingly, if the concentration of SiO.sub.2 in the glass composition is too high, the formability of the glass composition may be diminished as higher concentrations of SiO.sub.2 increase the difficulty of melting the glass, which in turn, adversely impacts the formability of the glass. In embodiments, the glass composition may comprise 50.0 to 70.0 mol % SiO.sub.2. In embodiments, the glass composition may comprise 55.0 to 65.0 mol % SiO.sub.2. In embodiments, the glass composition may comprise 57.0 to 63.0 mol % SiO.sub.2. In embodiments, the concentration of SiO.sub.2 in the glass composition may be in the range from 50.0 to 70.0 mol %, from 50.0 to 67.0 mol %, from 50.0 to 65.0 mol %, from 50.0 to 63.0 mol %, from 50.0 to 60.0 mol %, from 55.0 to 70.0 mol %, from 55.0 to 67.0 mol %, from 55.0 to 65.0 mol %, from 55.0 to 64.0 mol %, from 55.0 to 63.0 mol %, from 55.0 to 62.0 mol %, from 55.0 to 61.0 mol %, from 55.0 to 60.0 mol %, from 55.0 to 59.0 mol %, from 56.0 to 70.0 mol %, from 56.0 to 67.0 mol %, from 56.0 to 65.0 mol %, from 56.0 to 64.0 mol %, from 56.0 to 63.0 mol %, from 56.0 to 62.0 mol %, from 56.0 to 61.0 mol %, from 56.0 to 60.0 mol %, from 56.0 to 59.0 mol %, from 57.0 to 70.0 mol %, from 57.0 to 67.0 mol %, from 57.0 to 65.0 mol %, from 57.0 to 64.0 mol %, from 57.0 to 63.0 mol %, from 57.0 to 62.0 mol %, from 57.0 to 61.0 mol %, from 57.0 to 60.0 mol %, or from 57.0 to 59.0 mol %, or any and all sub-ranges formed from any of these endpoints.

(52) The glass compositions described herein may further comprise Al.sub.2O.sub.3. Al.sub.2O.sub.3 may serve as a glass network former, similar to SiO.sub.2. Al.sub.2O.sub.3 may increase the viscosity of the glass composition due to its tetrahedral coordination in a glass melt formed from a glass composition. If the amount of Al.sub.2O.sub.3 it too high, the formability of the glass composition may be decreased. However, when the concentration of Al.sub.2O.sub.3 is balanced against the concentration of SiO.sub.2 and the concentration of alkali oxides in the glass composition, Al.sub.2O.sub.3 may reduce the liquidus temperature of the glass melt. Reducing the liquidus temperature enhances the liquidus viscosity and improves the compatibility of the glass composition with certain forming processes, such as the fusion forming process. In embodiments, the glass composition may comprise from 10.0 to 25.0 mol % Al.sub.2O.sub.3. In embodiments, the glass composition may comprise from 14.0 to 20.0 mol % Al.sub.2O.sub.3. In embodiments, the glass composition may comprise from 15.0 to 19.0 mol % Al.sub.2O.sub.3. In embodiments, the concentration of Al.sub.2O.sub.3 in the glass composition may be in the range from 10.0 to 25.0 mol %, from 10.0 to 23.0 mol %, from 10.0 to 20.0 mol %, from 10.0 to 19.0 mol %, from 10.0 to 18.0 mol %, from 12.0 to 25.0 mol %, from 12.0 to 23.0 mol %, from 12.0 to 20.0 mol %, from 12.0 to 19.0 mol %, from 12.0 to 18.0 mol %, from 13.0 to 25.0 mol %, from 13.0 to 23.0 mol %, from 13.0 to 20.0 mol %, from 13.0 to 19.0 mol %, from 13.0 to 18.0 mol %, from 14.0 to 25.0 mol %, from 14.0 to 23.0 mol %, from 14.0 to 20.0 mol %, from 14.0 to 19.0 mol %, from 14.0 to 18.0 mol %, from 15.0 to 25.0 mol %, from 15.0 to 23.0 mol %, from 15.0 to 20.0 mol %, from 15.0 to 19.0 mol %, from 15.0 to 18.0 mol %, from 16.0 to 25.0 mol %, from 16.0 to 23.0 mol %, from 16.0 to 20.0 mol %, from 16.0 to 19.0 mol %, from 16.0 to 18.0 mol %, from 17.0 to 25.0 mol %, from 17.0 to 23.0 mol %, from 17.0 to 20.0 mol %, from 17.0 to 19.0 mol %, or from 17.0 to 18.0 mol %, or any and all sub-ranges formed from any of these endpoints. In embodiments, the concentration of Al.sub.2O.sub.3 in the glass composition may be greater than or equal to 10.0 mol %, greater than or equal to 11.0 mol %, greater than or equal to 12.0 mol %, greater than or equal to 13.0 mol %, greater than or equal to 14.0 mol %, greater than or equal to 15.0 mol %, greater than or equal to 16.0 mol %, or greater than or equal to 17.0 mol %.

(53) The glass compositions described herein may further comprise P.sub.2O.sub.5. Like SiO.sub.2 and Al.sub.2O.sub.3, P.sub.2O.sub.5 may be added to the glass composition as a network former, thereby reducing the meltability and formability of the glass composition. Thus, P.sub.2O.sub.5 may be added in amounts that do not overly decrease these properties. The addition of P.sub.2O.sub.5 may also increase the diffusivity of ions in the glass composition during ion exchange treatment, thereby increasing the efficiency of these treatments. In embodiments, the glass composition may comprise from 0.0 to 5.0 mol % P.sub.2O.sub.5. In embodiments, the glass composition may comprise from 0.3 to 3.0 mol % P.sub.2O.sub.5. In embodiments, the glass composition may comprise from 0.5 to 2.5 mol % P.sub.2O.sub.5. In embodiments, the concentration of P.sub.2O.sub.5 in the glass composition may be in the range from 0.0 to 5.0 mol %, from 0.0 to 4.0 mol %, from 0.0 to 3.0 mol %, from 0.0 to 2.5 mol %, from 0.0 to 2.3 mol %, from 0.0 to 2.0 mol %, from 0.0 to 1.7 mol %, from 0.0 to 1.5 mol %, from 0.3 to 5.0 mol %, from 0.3 to 4.0 mol %, from 0.3 to 3.0 mol %, from 0.3 to 2.5 mol %, from 0.3 to 2.3 mol %, from 0.3 to 2.0 mol %, from 0.3 to 1.7 mol %, from 0.3 to 1.5 mol %, from 0.5 to 5.0 mol %, from 0.5 to 4.0 mol %, from 0.5 to 3.0 mol %, from 0.5 to 2.5 mol %, from 0.5 to 2.3 mol %, from 0.5 to 2.0 mol %, from 0.5 to 1.7 mol %, from 0.5 to 1.5 mol %, from 0.7 to 5.0 mol %, from 0.7 to 4.0 mol %, from 0.7 to 3.0 mol %, from 0.7 to 2.5 mol %, from 0.7 to 2.3 mol %, from 0.7 to 2.0 mol %, from 0.7 to 1.7 mol %, from 0.7 to 1.5 mol %, from 1.0 to 5.0 mol %, from 1.0 to 4.0 mol %, from 1.0 to 3.0 mol %, from 1.0 to 2.5 mol %, from 1.0 to 2.3 mol %, from 1.0 to 2.0 mol %, from 1.0 to 1.7 mol %, or from 1.0 to 1.5 mol %, or any and all sub-ranges formed from any of these endpoints. In embodiments, the glass composition may comprise less than or equal to 4.0 mol % P.sub.2O.sub.5. In embodiments, the concentration of P.sub.2O.sub.5 in the glass composition may be less than or equal to 5.0 mol %, less than or equal to 4.5 mol %, less than or equal to 4.0 mol %, less than or equal to 3.5 mol %, less than or equal to 3.0 mol %, less than or equal to 2.5 mol %, less than or equal to 2.0 mol %, or less than or equal to 1.5 mol %.

(54) The glass compositions described herein may further comprise B.sub.2O.sub.3. Like SiO.sub.2, Al.sub.2O.sub.3, and P.sub.2O.sub.5, B.sub.2O.sub.3 may be added to the glass composition as a network former, thereby reducing the meltability and formability of the glass composition. Thus, B.sub.2O.sub.3 may be added in amounts that do not overly decrease these properties. However, it has been found that additions of boron significantly reduce diffusivity of alkali ions in the glass composition, which, in turn, adversely impacts the ion exchange performance of the resultant glass. In particular, it has been found that additions of boron significantly increase the time required to achieve a given CT and/or DOC relative to glass compositions which are boron free. In embodiments, the glass composition may comprise from 0.0 to 10.0 mol % B.sub.2O.sub.3. In embodiments, the glass composition may comprise from 1.0 to 7.0 mol % B.sub.2O.sub.3. In embodiments, the glass composition may comprise from 2.0 to 6.0 mol % B.sub.2O.sub.3. In embodiments, the concentration of B.sub.2O.sub.3 in the glass composition may be in the range from 0.0 to 10.0 mol %, from 0.0 to 9.0 mol %, 0.0 to 8.0 mol %, 0.0 to 7.5 mol %, 0.0 to 7.0 mol %, 0.0 to 6.5 mol %, from 0.0 to 6.0 mol %, from 0.0 to 5.5 mol %, from 0.0 to 5.0 mol %, from 0.0 to 4.5 mol %, from 0.5 to 10.0 mol %, from 0.5 to 9.0 mol %, 0.5 to 8.0 mol %, 0.5 to 7.5 mol %, 0.5 to 7.0 mol %, 0.5 to 6.5 mol %, from 0.5 to 6.0 mol %, from 0.5 to 5.5 mol %, from 0.5 to 5.0 mol %, from 0.5 to 4.5 mol %, from 1.0 to 10.0 mol %, from 1.0 to 9.0 mol %, 1.0 to 8.0 mol %, 1.0 to 7.5 mol %, 1.0 to 7.0 mol %, 1.0 to 6.5 mol %, from 1.0 to 6.0 mol %, from 1.0 to 5.5 mol %, from 1.0 to 5.0 mol %, from 1.0 to 4.5 mol %, from 1.5 to 10.0 mol %, from 1.5 to 9.0 mol %, from 1.5 to 8.0 mol %, from 1.5 to 7.5 mol %, from 1.5 to 7.0 mol %, from 1.5 to 6.5 mol %, from 1.5 to 6.0 mol %, from 1.5 to 5.5 mol %, from 1.5 to 5.0 mol %, from 1.5 to 4.5 mol %, from 2.0 to 10 mol %, from 2.0 to 9.0 mol %, from 2.0 to 8.0 mol %, from 2.0 to 7.5 mol %, from 2.0 to 7.0 mol %, from 2.0 to 6.5 mol %, from 2.0 to 6.0 mol %, from 2.0 to 5.5 mol %, from 2.0 to 5.0 mol %, from 2.0 to 4.5 mol %, from 2.5 to 10.0 mol %, from 2.5 to 9.0 mol %, from 2.5 to 8.0 mol %, from 2.5 to 7.5 mol %, from 2.5 to 7.0 mol %, from 2.5 to 6.5 mol %, from 0.0 to 6.0 mol %, from 0.0 to 5.5 mol %, from 2.5 to 5.0 mol %, from 2.5 to 4.5 mol %, from 3.0 to 10.0 mol %, from 3.0 to 9.0 mol %, from 3.0 to 8.0 mol %, from 3.0 to 7.5 mol %, from 3.0 to 7.0 mol %, from 3.0 to 6.5 mol %, from 3.0 to 6.0 mol %, from 3.0 to 5.5 mol %, from 3.0 to 5.0 mol %, from 3.0 to 4.5 mol %, from 3.5 to 10.0 mol %, from 3.5 to 9.0 mol %, from 3.5 to 8.0 mol %, from 3.5 to 7.5 mol %, from 3.5 to 7.0 mol %, from 3.5 to 6.5 mol %, from 3.5 to 6.0 mol %, from 3.5 to 5.5 mol %, from 3.5 to 5.0 mol %, from 3.5 to 4.5 mol %, from 4.0 to 10.0 mol %, from 4.0 to 9.0 mol %, from 4.0 to 8.0 mol %, from 4.0 to 7.5 mol %, from 4.0 to 7.0 mol %, from 4.0 to 6.5 mol %, from 4.0 to 6.0 mol %, from 4.0 to 5.5 mol %, or from 4.0 to 5.0 mol %, or any and all sub-ranges formed from any of these endpoints. In embodiments, the concentration of B.sub.2O.sub.3 in the glass composition may be greater than or equal to 0.5 mol %, greater than or equal to 1.0 mol %, greater than or equal to 1.5 mol %, greater than or equal to 2.0 mol %, greater than or equal to 2.5 mol %, greater than or equal to 3.0 mol %, greater than or equal to 3.5 mol %, or greater than or equal to 4.0 mol %.

(55) In embodiments, the glass compositions described herein may include a relatively high SiO.sub.2 concentration to increase durability, and may also include B.sub.2O.sub.3 and Al.sub.2O.sub.3 to increase scratch resistance and P.sub.2O.sub.5 to improve ion-exchange properties. In embodiments, the glass composition may satisfy the relationship (B.sub.2O.sub.3+P.sub.2O.sub.5+Al.sub.2O.sub.3)/(SiO.sub.2)≥0.20, (B.sub.2O.sub.3+P.sub.2O.sub.5+Al.sub.2O.sub.3)/(SiO.sub.2)≥0.30, or (B.sub.2O.sub.3+P.sub.2O.sub.5+Al.sub.2O.sub.3)/(SiO.sub.2)≥0.40. Accordingly, balance the amounts of B.sub.2O.sub.3, P.sub.2O.sub.5, and Al.sub.2O.sub.3 to be within the above ranges provides a balance of diffusivity and fracture toughness.

(56) The glass compositions described herein may further comprise Li.sub.2O. The effects of Li.sub.2O in the glass composition are discussed above. In part, the addition of lithium in the glass allows for better control of an ion exchange process and further reduces the softening point of the glass. In embodiments, the glass composition may comprise 5.0 to 15.0 mol % Li.sub.2O. In embodiments, the glass composition may comprise 5.0 to 10.0 mol % Li.sub.2O. In embodiments, the glass composition may comprise 6.0 to 9.0 mol % Li.sub.2O. In embodiments, the concentration of Li.sub.2O in the glass composition may be in the range from 5.0 to 15.0 mol %, from 5.0 to 10.0 mol %, from 5.0 to 9.0 mol %, from 5.0 to 8.5 mol %, from 5.0 to 8.0 mol %, from 6.0 to 15.0 mol %, from 6.0 to 10.0 mol %, from 6.0 to 9.0 mol %, from 6.0 to 8.5 mol %, from 6.0 to 8.0 mol %, from 6.0 to 7.5 mol %, from 6.0 to 7.0 mol %, from 6.5 to 15.0 mol %, from 6.5 to 10.0 mol %, from 6.5 to 9.0 mol %, from 6.5 to 8.5 mol %, from 6.5 to 8.0 mol %, from 7.0 to 15.0 mol %, from 7.0 to 10.0 mol %, from 7.0 to 9.0 mol %, from 7.0 to 8.5 mol %, from 7.0 to 8.0 mol %, 7.5 to 15.0 mol %, from 7.5 to 10.0 mol %, from 7.5 to 9.0 mol %, or from 7.5 to 8.5 mol %, or any and all sub-ranges formed from any of these endpoints. In embodiments, the concentration of Li.sub.2O in the glass composition may be less than or equal to 15.0 mol %, less than or equal to 10.0 mol %, less than or equal to 9.5 mol %, less than or equal to 9.0 mol %, less than or equal to 8.5 mol %, or less than or equal to 8.0 mol %.

(57) The glass compositions described herein may further comprise alkali metal oxides other than Li.sub.2O, such as Na.sub.2O. Na.sub.2O aids in the ion exchangeability of the glass composition, and also increases the melting point and improves formability of the glass composition. However, if too much Na.sub.2O is added to the glass composition, the CTE may be too low and the melting point may be too high. As such, in embodiments, the concentration of Li.sub.2O present in the glass composition is greater than the concentration of Na.sub.2O present in the glass composition. In embodiments, the glass composition may comprise 1.0 to 15.0 mol % Na.sub.2O. In embodiments, the glass composition may comprise 4.0 to 10.0 mol % Na.sub.2O. In embodiments, the glass composition may comprise 5.0 to 9.0 mol % Na.sub.2O. In embodiments, the concentration of Na.sub.2O in the glass composition may be in the range from 1.0 to 15.0 mol %, from 1.0 to 10.0 mol %, from 3.0 to 15.0 mol %, from 3.0 to 10.0 mol %, from 4.0 to 15.0 mol %, from 4.0 to 10.0 mol %, from 4.0 to 9.5 mol %, from 4.0 to 9.0 mol %, from 4.5 to 15.0 mol %, from 4.5 to 10.0 mol %, from 4.5 to 9.5 mol %, from 4.5 to 9.0 mol %, from 5.0 to 15 mol %, from 5.0 to 10.0 mol %, from 5.0 to 9.5 mol %, from 5.0 to 9.0 mol %, from 5.5 to 15.0 mol %, from 5.5 to 10.0 mol %, from 5.5 to 9.5 mol %, from 5.5 to 9.0 mol %, from 6.0 to 15.0 mol %, from 6.0 to 10.0 mol %, from 6.0 to 9.5 mol %, from 6.0 to 9.0 mol %, from 6.5 to 15.0 mol %, from 6.5 to 10.0 mol %, from 6.5 to 9.5 mol %, from 6.5 to 9.0 mol %, from 7.0 to 15.0 mol %, from 7.0 to 10.0 mol %, from 7.0 to 9.5 mol %, from 7.0 to 9.0 mol %, from 7.5 to 15.0 mol %, from 7.5 to 10.0 mol %, from 7.5 to 9.5 mol %, from 8.0 to 15.0 mol %, or from 8.0 to 10.0 mol % or any and all sub-ranges formed from any of these endpoints. In embodiments, the concentration of Na.sub.2O in the glass composition may be less than or equal to 15.0 mol %, less than or equal to 10.0 mol %, less than or equal to 9.5 mol %, or less than or equal to 9.0 mol.

(58) The glass compositions described herein may further comprise alkali metal oxides other than Li.sub.2O and Na.sub.2O, such as K.sub.2O. K.sub.2O promotes ion exchange and increases the DOC. However, adding K.sub.2O may cause the CTE to be too low and the melting point to be too high. In embodiments, the glass composition may comprise 0.0 to 1.0 mol % K.sub.2O. In embodiments, the glass composition may comprise 0.0 to 0.5 mol % K.sub.2O. In embodiments, the glass composition may comprise 0.0 to 0.4 mol % K.sub.2O. In embodiments, the concentration of K.sub.2O in the glass composition may be in the range from 0.0 to 1.0 mol %, from 0.0 to 0.5 mol %, from 0.0 to 0.4 mol %, from 0.0 to 0.3 mol %, from 0.0 to 0.2 mol %, or from 0.0 to 0.1 mol %, or any and all sub-ranges formed from any of these endpoints. In embodiments, the glass composition may comprise less than or equal to 1.0 mol % K.sub.2O, less than or equal to 0.5 mol % K.sub.2O, less than or equal to 0.4 mol % K.sub.2O, less than or equal to 0.3 mol % K.sub.2O, less than or equal to 0.2 mol % K.sub.2O, or less than or equal to 0.1 mol % K.sub.2O.

(59) The sum of all alkali oxides is expressed herein as R.sub.2O. The alkali oxides aid in decreasing the softening point and molding temperature of the glass composition, thereby offsetting the increase in the softening point and molding temperature of the glass composition due to higher amounts of SiO.sub.2 in the glass composition. The decrease in the softening point and molding temperature may be further enhanced by including combinations of alkali oxides (e.g., two or more alkali oxides) in the glass composition, a phenomenon referred to as the “mixed alkali effect.” However, it has been found that if the amount of alkali oxide is too high, the average coefficient of thermal expansion of the glass composition increases to greater than 100×10.sup.−7/° C., which may be undesirable.

(60) In embodiments, the amount of R.sub.2O in the glass composition may be in the range from greater than or equal to 11.0 mol % to less than or equal to 23.0 mol %, from greater than or equal to 11.0 mol % to less than or equal to 22.0 mol %, from greater than or equal to 11.0 mol % to less than or equal to 21.0 mol %, from greater than or equal to 11.0 mol % to less than or equal to 20.0 mol %, from greater than or equal to 11.0 mol % to less than or equal to 19.0 mol %, from greater than or equal to 11.0 mol % to less than or equal to 18.0 mol %, from greater than or equal to 11.0 mol % to less than or equal to 17.0 mol %, from greater than or equal to 13.0 mol % to less than or equal to 23.0 mol %, from greater than or equal to 13.0 mol % to less than or equal to 22.0 mol %, from greater than or equal to 13.0 mol % to less than or equal to 21.0 mol %, from greater than or equal to 13.0 mol % to less than or equal to 20.0 mol %, from greater than or equal to 13.0 mol % to less than or equal to 19.0 mol %, from greater than or equal to 13.0 mol % to less than or equal to 18.0 mol %, from greater than or equal to 13.0 mol % to less than or equal to 17.0 mol %, from greater than or equal to 15.0 mol % to less than or equal to 23.0 mol %, from greater than or equal to 15.0 mol % to less than or equal to 22.0 mol %, from greater than or equal to 15.0 mol % to less than or equal to 21.0 mol %, from greater than or equal to 15.0 mol % to less than or equal to 20.0 mol %, from greater than or equal to 15.0 mol % to less than or equal to 19.0 mol %, from greater than or equal to 15.0 mol % to less than or equal to 18.0 mol %, or from greater than or equal to 15.0 mol % to less than or equal to 17.0 mol %. It should be understood that the amount of R.sub.2O in the glass compositions may be within a range formed from any one of the lower bounds of R.sub.2O and any one of the upper bounds of R.sub.2O described herein.

(61) In addition to being a glass network forming component, Al.sub.2O.sub.3 aids in increasing the ion exchangeability of the glass composition. Therefore, in embodiments, the amount of Al.sub.2O.sub.3 and components that may be ion exchanged may be relatively high. For example, Li.sub.2O, Na.sub.2O, and K.sub.2O are ion exchangeable components. In embodiments, the amount of Al.sub.2O.sub.3+R.sub.2O in the glass composition may be in the range from greater than or equal to 26.0 mol % to less than or equal to 40.0 mol %, from greater than or equal to 28.0 mol % to less than or equal to 40.0 mol %, from greater than or equal to 30.0 mol % to less than or equal to 40.0 mol %, from greater than or equal to 32.0 mol % to less than or equal to 40.0 mol %, from greater than or equal to 34.0 mol % to less than or equal to 40.0 mol %, from greater than or equal to 26.0 mol % to less than or equal to 38.0 mol %, from greater than or equal to 28.0 mol % to less than or equal to 38.0 mol %, from greater than or equal to 30.0 mol % to less than or equal to 38.0 mol %, from greater than or equal to 32.0 mol % to less than or equal to 38.0 mol %, from greater than or equal to 34.0 mol % to less than or equal to 38.0 mol %, from greater than or equal to 26.0 mol % to less than or equal to 36.0 mol %, from greater than or equal to 28.0 mol % to less than or equal to 36.0 mol %, from greater than or equal to 30.0 mol % to less than or equal to 36.0 mol %, from greater than or equal to 32.0 mol % to less than or equal to 36.0 mol %, or from greater than or equal to 34.0 mol % to less than or equal to 36.0 mol %. It should be understood that the amount of Al.sub.2O.sub.3+R.sub.2O in the glass compositions may be within a range formed from any one of the lower bounds of Al.sub.2O.sub.3+R.sub.2O and any one of the upper bounds of Al.sub.2O.sub.3+R.sub.2O described herein. Having a sum of Al.sub.2O.sub.3+R.sub.2O within the ranges described above provides a high compressive stress in strengthened glass articles and good diffusivity.

(62) In embodiments, the amount of Al.sub.2O.sub.3+R.sub.2O+B.sub.2O.sub.3 in the glass composition is greater than or equal to 30.0 mol %, greater than or equal to 32.0 mol %, greater than or equal to 34.0 mol %, greater than or equal to 36.0 mol %, or greater than or equal to 38.0 mol %. In embodiments, the amount of Al.sub.2O.sub.3+R.sub.2O+B.sub.2O.sub.3 in the glass composition may be in the range from greater than or equal to 30.0 mol % to less than or equal to 40.0 mol %, from greater than or equal to 30.0 mol % to less than or equal to 38.0 mol %, from greater than or equal to 30.0 mol % to less than or equal to 36.0 mol %, from greater than or equal to 30.0 mol % to less than or equal to 34.0 mol %, from greater than or equal to 30.0 mol % to less than or equal to 32.0 mol %, from greater than or equal to 32.0 mol % to less than or equal to 40.0 mol %, from greater than or equal to 32.0 mol % to less than or equal to 38.0 mol %, from greater than or equal to 32.0 mol % to less than or equal to 36.0 mol %, from greater than or equal to 32.0 mol % to less than or equal to 34.0 mol %, from greater than or equal to 34.0 mol % to less than or equal to 40.0 mol %, from greater than or equal to 34.0 mol % to less than or equal to 38.0 mol %, from greater than or equal to 34.0 mol % to less than or equal to 36.0 mol %, from greater than or equal to 36.0 mol % to less than or equal to 40.0 mol %, from greater than or equal to 36.0 mol % to less than or equal to 38.0 mol %, or from greater than or equal to 38.0 mol % to less than or equal to 40.0 mol %. It should be understood that the amount of Al.sub.2O.sub.3+R.sub.2O+B.sub.2O.sub.3 in the glass compositions may be within a range formed from any one of the lower bounds of Al.sub.2O.sub.3+R.sub.2O+B.sub.2O.sub.3 and any one of the upper bounds of Al.sub.2O.sub.3+R.sub.2O+B.sub.2O.sub.3 described herein. As mentioned above, having a sum of Al.sub.2O.sub.3+R.sub.2O within the ranges described herein provides a high compressive stress in strengthened glass articles and good diffusivity, and B.sub.2O.sub.3 lowers the softening point of the glass composition. Accordingly, having a sum of Al.sub.2O.sub.3+R.sub.2O+B.sub.2O.sub.3 within the ranges described above allows for glass compositions to have good compressive stress upon ion exchange in conjunction with good formability provided by a lower softening point.

(63) The glass compositions described herein may further comprise MgO. MgO lowers the viscosity of a glass, which enhances the formability, the strain point, and the Young's modulus, and may improve the ion exchangeability. However, when too much MgO is added to the glass composition, the density and the CTE of the glass composition increase. In embodiments, the concentration of MgO in the glass composition may be in the range from 0.0 to 5.0 mol %, from 0.0 to 4.5 mol %, from 0.0 to 4.0 mol %, from 0.0 to 3.5 mol %, from 0.0 to 3.0 mol %, from 0.0 to 2.5 mol %, from 0.0 to 2.0 mol %, from 0.0 to 1.5 mol %, from 0.5 to 5.0 mol %, from 0.5 to 4.5 mol %, from 0.5 to 4.0 mol %, from 0.5 to 3.5 mol %, from 0.5 to 3.0 mol %, from 0.5 to 2.5 mol %, from 0.5 to 2.0 mol %, from 0.5 to 1.5 mol %, from 1.0 to 5.0 mol %, from 1.0 to 4.5 mol %, from 1.0 to 4.0 mol %, from 1.0 to 3.5 mol %, from 1.0 to 3.0 mol %, from 1.0 to 2.5 mol %, from 1.0 to 2.0 mol %, or from 1.0 to 1.5 mol %, or any and all sub-ranges formed from any of these endpoints. In embodiments, the concentration of MgO is less than or equal to 5.0 mol %, less than or equal to 4.5 mol %, less than or equal to 4.0 mol %, less than or equal to 3.5 mol %, less than or equal to 3.0 mol %, less than or equal to 2.5 mol %, less than or equal to 2.0 mol %, or less than or equal to 1.5 mol %. In embodiments, the concentration of MgO in the glass composition may be from greater than 0.0 mol % to less than or equal to 3.0 mol %, from greater than 0.0 mol % to less than or equal to 2.5 mol %, from greater than 0.0 mol % to less than or equal to 2.0 mol %, or from greater than 0.0 mol % to less than or equal to 1.5 mol %.

(64) The glass compositions described herein may further comprise CaO. CaO lowers the viscosity of a glass, which enhances the formability, the strain point and the Young's modulus, and may improve the ion exchangeability. However, when too much CaO is added to the glass composition, the density and the CTE of the glass composition increase. In embodiments, the concentration of CaO in the glass composition may be from 0.0 to 5.0 mol %, from 0.0 to 4.0 mol %, from 0.0 to 3.5 mol %, from 0.0 to 3.0 mol %, from 0.0 to 2.5 mol %, from 0.0 to 2.0 mol %, from 0.0 to 1.5 mol %, from 0.0 to 1.0 mol %, from 0.0 to 0.5 mol %, from 0.0 to 0.1 mol %, from 0.5 to 5.0 mol %, from 0.5 to 4.0 mol %, from 0.5 to 3.5 mol %, from 0.5 to 3.0 mol %, from 0.5 to 2.5 mol %, from 0.5 to 2.0 mol %, from 0.5 to 1.5 mol %, from 0.5 to 1.0 mol %, from 1.0 to 5.0 mol %, from 1.0 to 4.0 mol %, from 1.0 to 3.5 mol %, from 1.0 to 3.0 mol %, from 1.0 to 2.5 mol %, from 1.0 to 2.0 mol %, from 1.5 to 5.0 mol %, from 1.5 to 4.0 mol %, from 1.5 to 3.5 mol %, from 1.5 to 3.0 mol %, from 1.5 to 2.5 mol %, from 1.5 to 2.0 mol %, from 2.0 to 5.0 mol %, from 2.0 to 4.0 mol %, from 2.0 to 3.5 mol %, from 2.0 to 3.0 mol %, from 2.0 to 2.5 mol %, from 2.5 to 5.0 mol %, from 2.5 to 4.0 mol %, from 2.5 to 3.5 mol %, or from 2.5 to 3.0 mol %, or any and all sub-ranges formed from any of these endpoints. In embodiments, the concentration of CaO in the glass composition may be less than or equal to 0.1 mol %. In embodiments, the concentration of CaO in the glass composition may be from greater than 0.0 mol % to less than 0.1 mol %. In embodiments, the glass composition may be substantially free or free of CaO.

(65) The glass compositions described herein may further include one or more fining agents. In embodiments, the fining agents may include, for example, SnO.sub.2. In embodiments, the concentration of SnO.sub.2 in the glass composition may be from 0.0 to 1.0 mol %, from 0.0 to 0.5 mol %, from 0.0 to 0.4 mol %, from 0.0 to 0.3 mol %, from 0.0 to 0.2 mol %, or from 0.0 to 0.1 mol %, or any and all sub-ranges formed from any of these endpoints. In embodiments, the concentration of SnO.sub.2 in the glass composition may be less than or equal to 0.1 mol %. In embodiments, the concentration of SnO.sub.2 in the glass composition may be in the range from greater than 0.0 mol % to less than or equal to 0.1 mol %, from greater than 0.0 mol % to less than or equal to 0.5 mol %, or from greater than 0.0 mol % to less than or equal to 1.0 mol %. In embodiments, the glass composition may be substantially free or free of SnO.sub.2.

(66) The glass compositions described herein may further include TiO.sub.2. TiO.sub.2 improves the UV absorbance of the glass composition. In embodiments, the concentration of TiO.sub.2 in the glass composition may be from 0.0 to 2.0 mol %, from 0.0 to 1.5 mol %, from 0.0 to 1.0 mol %, from 0.0 to 0.5 mol %, from 0.0 to 0.4 mol %, from 0.0 to 0.3 mol %, from 0.0 to 0.2 mol %, from 0.0 to 0.1 mol %, or any and all sub-ranges formed from any of these endpoints. In embodiments, the concentration of TiO.sub.2 in the glass composition may be from greater than 0.0 mol % to less than or equal to 1.5 mol % or from greater than 0.0 mol % to less than or equal to 2.0 mol %. In embodiments, the glass composition may be substantially free or free of TiO.sub.2.

(67) The glass compositions described herein may further include Fe.sub.2O.sub.3. In embodiments, the concentration of Fe.sub.2O.sub.3 in the glass composition may be from 0.0 to 1.0 mol %, from 0.0 to 0.5 mol %, from 0.0 to 0.4 mol %, from 0.0 to 0.3 mol %, from 0.0 to 0.2 mol %, or from 0.0 to 0.1 mol %, or any and all sub-ranges formed from any of these endpoints. In embodiments, the concentration of Fe.sub.2O.sub.3 in the glass composition may be less than or equal to 0.1 mol %. In embodiments, the concentration of Fe.sub.2O.sub.3 in the glass composition may be greater than 0.0 mol % to less than or equal to 0.1 mol %. In embodiments, the glass composition may be substantially free or free of Fe.sub.2O.sub.3.

(68) In embodiments, the glass compositions described herein may further comprise divalent cation oxides (referred herein as RO). As used herein, RO includes, but is not limited to MgO, CaO, SrO, BaO, FeO, and ZnO. In embodiments, the concentration of RO in the glass composition may be from 0.0 to 5.0 mol %, from 0.0 to 4.0 mol %, from 0.0 to 3.0 mol %, from 0.0 to 2.0 mol %, from 0.0 to 1.0 mol %, from 1.0 to 5.0 mol %, from 1.0 to 4.0 mol %, from 1.0 to 3.0 mol %, from 1.0 to 2.0 mol %, from 2.0 to 5.0 mol %, from 2.0 to 4.0 mol %, from 2.0 to 3.0 mol %, from 3.0 to 5.0 mol %, from 3.0 to 4.0 mol %, or from 4.0 to 5.0 mol %, or any and all sub-ranges formed from any of these endpoints.

(69) In embodiments, the glass composition is peraluminous (i.e., the amount of Al.sub.2O.sub.3 in the glass composition is greater than the sum of Li.sub.2O, Na.sub.2O, K.sub.2O and MgO), which may increase the Knoop Scratch threshold of the glass composition. In embodiments, the glass composition may satisfy the relationship 0.9≤Al.sub.2O.sub.3/(R.sub.2O+RO)≤1.1 to achieve charge balance, which maximizes the strengthening process by increasing diffusivity. However, when the glass composition becomes peraluminus, the benefits of this charge balance are no longer achieved. Further, as the Al.sub.2O.sub.3/(R.sub.2O+RO) ratio increases above 1.0, the melting point becomes high, making processing and forming difficult.

(70) In embodiments, controlling the amount of Li.sub.2O in the glass composition allows the glass to be peraluminous. In embodiments, the glass composition may satisfy the relationship −0.1≤(Al.sub.2O.sub.3−(R.sub.2O+RO))/Li.sub.2O≤0.3. In embodiments, the glass composition may satisfy the relationship −0.1≤(Al.sub.2O.sub.3−(R.sub.2O+RO))/Li.sub.2O≤0.2, −0.1≤(Al.sub.2O.sub.3−(R.sub.2O+RO))/Li.sub.2O≤0.1, −0.1≤(Al.sub.2O.sub.3−(R.sub.2O+RO))/Li.sub.2O≤0.05, 0.0≤(Al.sub.2O.sub.3−(R.sub.2O+RO))/Li.sub.2O≤0.3, 0.0≤(Al.sub.2O.sub.3−(R.sub.2O+RO))/Li.sub.2O≤0.2, 0.0≤(Al.sub.2O.sub.3−(R.sub.2O+RO))/Li.sub.2O≤0.1, or 0.0 (Al.sub.2O.sub.3−(R.sub.2O+RO))/Li.sub.2O≤0.05. It should be understood that the relationship may be within a sub-range formed from any and all of the foregoing endpoints.

(71) In embodiments, the glass composition may satisfy the relationship Al.sub.2O.sub.3*(10.832)+B.sub.2O.sub.3*(10.334)+P.sub.2O.sub.5*(−13.761)+Li.sub.2O*(−3.135)+Na.sub.2O*(−7.213)+K.sub.2O*(−13.761)+MgO*(2.159)+CaO*(−4.518)+SrO*(−4.518)>100. According to embodiments, glass compositions meeting this inequality have a desired fracture toughness. In embodiments, the glass composition may satisfy the relationship Al.sub.2O.sub.3*(5.99)+B.sub.2O.sub.3*(−3.85)+P.sub.2O.sub.5*(−8.44)+Li.sub.2O*(8.65)+Na.sub.2O*(−4.65)+K.sub.2O*(−10.18)+MgO*(1.86)+CaO*(1.86)+SrO*(1.86)>100. According to embodiments, glass compositions meeting this inequality have desired compressive stress. In embodiments, the glass composition may satisfy the relationship Al.sub.2O.sub.3*(4.52)+B.sub.2O*(−8.28)+P.sub.2O.sub.5*(−1.73)+Li.sub.2O*(−10.40)+Na.sub.2O*(−7.65)+K.sub.2O*(−10.52)+MgO*(−4.33)+CaO*(−6.61)+SrO*(−2.60)<−100. According to embodiments, glass compositions meeting this inequality have a deserved softening point. It should be understood that glass compositions may satisfy one or more of the above inequalities according to embodiments and the desired properties (such as fracture toughness, compressive stress, and softening point) of the glass composition.

(72) In embodiments, the glass compositions described herein may further include tramp materials such as MnO, MoO.sub.3, W.sub.3, Y.sub.2O.sub.3, La.sub.2O.sub.3, CdO, As.sub.2O.sub.3, Sb.sub.2O.sub.3, sulfur-based compounds, such as sulfates, halogens, or combinations thereof. In embodiments, antimicrobial components, or other additional components may be included in the glass compositions.

(73) In embodiments, the glass composition comprises 57.0 mol % to 64.0 mol % SiO.sub.2; 17.0 mol % to 19.0 mol % Al.sub.2O.sub.3; 1.0 mol % to 3.0 mol % P.sub.2O.sub.5; 0.0 mol % to 5.0 mol % B.sub.2O.sub.3; 7.5 mol % to 9.0 mol % Li.sub.2O; 7.0 mol % to 9.0 mol % Na.sub.2O; and 0.0 mol % to 0.3 mol % K.sub.2O. The sum of all alkali oxides, R.sub.2O, present in the glass composition may be in the range from greater than or equal to 15.0 mol % to less than or equal to 18.0 mol %. The sum of Al.sub.2O.sub.3 and R.sub.2O present in the glass composition may be in the range from greater than or equal to 34.0 mol % to less than or equal to 36.0 mol %. The glass composition may satisfy the relationship −0.1≤(Al.sub.2O.sub.3−(R.sub.2O+RO))/Li.sub.2O≤0.3.

(74) In embodiments, the glass composition comprises 57.0 mol % to 67.0 mol % SiO.sub.2; 15.0 mol % to 18.0 mol % Al.sub.2O.sub.3; 0.5 mol % to 1.5 mol % P.sub.2O.sub.5; 2.0 mol % to 7.0 mol % B.sub.2O.sub.3; 6.0 mol % to 8.0 mol % Li.sub.2O; 4.0 mol % to 9.0 mol % Na.sub.2O; and 0.0 mol % to 0.3 mol % K.sub.2O. The sum of all alkali oxides, R.sub.2O, present in the glass composition may be in the range from greater than or equal to 11.0 mol % to less than or equal to 13.0 mol %. The sum of Al.sub.2O.sub.3 and R.sub.2O present in the glass composition may be in the range from greater than or equal to 26.0 mol % to less than or equal to 36.0 mol %. The glass composition may satisfy the relationship −0.1≤(Al.sub.2O.sub.3−(R.sub.2O+RO))/Li.sub.2O≤0.3.

(75) In embodiments, the glass composition comprises 55.0 mol % to 62.0 mol % SiO.sub.2; 10.0 mol % to 19.0 mol % Al.sub.2O.sub.3; 0.0 mol % to 10.0 mol % P.sub.2O.sub.5; 2.0 mol % to 8.0 mol % B.sub.2O.sub.3; 6.0 mol % to 8.0 mol % Li.sub.2O; 7.0 mol % to 10.0 mol % Na.sub.2O; and 0.0 mol % to 0.5 mol % K.sub.2O. The sum of all alkali oxides, R.sub.2O, present in the glass composition may be in the range from greater than or equal to 15.0 mol % to less than or equal to 19.0 mol %. The sum of Al.sub.2O.sub.3 and R.sub.2O present in the glass composition may be in the range from greater than or equal to 28.0 mol % to less than or equal to 36.0 mol %. The glass composition may satisfy the relationship −0.1≤(Al.sub.2O.sub.3−(R.sub.2O+RO))/Li.sub.2O≤0.3.

(76) In embodiments, the glass composition comprises 55.0 mol % to 65.0 mol % SiO.sub.2; 14.0 mol % to 20.0 mol % Al.sub.2O.sub.3; 0.0 mol % to 3.0 mol % P.sub.2O.sub.5; 1.0 mol % to 7.0 mol % B.sub.2O.sub.3; 5.0 mol % to 10.0 mol % Li.sub.2O; 5.0 mol % to 10.0 mol % Na.sub.2O; and 0.0 mol % to 1.0 mol % K.sub.2O. The sum of all alkali oxides, R.sub.2O, present in the glass composition may be in the range from greater than or equal to 13.0 mol % to less than or equal to 20.0 mol %. The sum of Al.sub.2O.sub.3 and R.sub.2O present in the glass composition may be in the range from greater than or equal to 28.0 mol % to less than or equal to 40.0 mol %. The glass composition may satisfy the relationship −0.1≤(Al.sub.2O.sub.3−(R.sub.2O+RO))/Li.sub.2O≤0.3.

(77) In embodiments, the glass composition comprises 55.0 mol % to 63.0 mol % SiO.sub.2; 15.0 mol % to 19.0 mol % Al.sub.2O.sub.3; 0.5 mol % to 2.5 mol % P.sub.2O.sub.5; 2.0 mol % to 6.0 mol % B.sub.2O.sub.3; 6.0 mol % to 10.0 mol % Li.sub.2O; 6.0 mol % to 10.0 mol % Na.sub.2O; and 0.0 mol % to 0.5 mol % K.sub.2O. The sum of all alkali oxides, R.sub.2O, present in the glass composition may be in the range from greater than or equal to 15.0 mol % to less than or equal to 20.0 mol %. The sum of Al.sub.2O.sub.3 and R.sub.2O present in the glass composition may be in the range from greater than or equal to 30.0 mol % to less than or equal to 38.0 mol %. The glass composition may satisfy the relationship −0.1≤(Al.sub.2O.sub.3−(R.sub.2O+RO))/Li.sub.2O≤0.3.

(78) In embodiments, the glass composition comprises 56.0 mol % to 60.0 mol % SiO.sub.2; 16.0 mol % to 18.0 mol % Al.sub.2O.sub.3; 1.0 mol % to 2.0 mol % P.sub.2O.sub.5; 3.0 mol % to 5.0 mol % B.sub.2O.sub.3; 6.0 mol % to 9.0 mol % Li.sub.2O; 7.0 mol % to 9.0 mol % Na.sub.2O; and 0.0 mol % to 0.1 mol % K.sub.2O. The sum of all alkali oxides, R.sub.2O, present in the glass composition may be in the range from greater than or equal to 15.0 mol % to less than or equal to 17.0 mol %. The sum of Al.sub.2O.sub.3 and R.sub.2O present in the glass composition may be in the range from greater than or equal to 32.0 mol % to less than or equal to 36.0 mol %. The glass composition may satisfy the relationship −0.1≤(Al.sub.2O.sub.3−(R.sub.2O+RO))/Li.sub.2O≤0.3.

(79) Physical properties of the alkali aluminosilicate glass compositions as disclosed above will now be discussed. These physical properties can be achieved by modifying the component amounts of the alkali aluminosilicate glass compositions, as will be discussed in more detail with reference to the examples.

(80) The articles formed from the glass compositions described herein may be any suitable thickness (t), which may vary depending on the particular application for use of the glass. The thickness is defined by opposing first and second surfaces of a glass substrate. Glass article embodiments may have a thickness of from 0.3 to 3 mm. In embodiments, the glass article may have a thickness of 5.0 mm or less, 4.5 mm or less, 4.0 mm or less, 3.5 mm or less, 3.0 mm or less, 2.5 mm or less, 2.0 mm or less, 1.0 mm or less, 0.9 mm or less, 0.8 mm or less, 0.7 mm or less, 0.6 mm or less, 0.5 mm or less, 0.4 mm or less, 0.3 mm or less, 0.2 mm or less, 0.1 mm or less, 750.0 μm or less, 500.0 μm or less, or 250.0 μm or less. In embodiments, the glass article may have a thickness of from 200.0 μm to 5.0 mm, from 500.0 μm to 5.0 mm, from 200.0 μm to 4.0 mm, from 500.0 μm to 4.0 mm, from 200.0 μm to 3.0 mm, or from 500.0 μm to 3.0 mm. In embodiments, the glass article may have a thickness in the range from 0.1 mm to 5.0 mm, from 0.2 to 5.0 mm, from 0.3 to 5.0 mm, from 0.4 to 5.0 mm, from 0.5 to 5.0 mm, from 0.1 mm to 3.0 mm, from 0.2 to 3.0 mm, from 0.3 to 3.0 mm, from 0.4 to 3.0 mm, or from 0.5 to 3.0 mm. According to embodiments, the glass article has a thickness greater than or equal to 100 μm and less then or equal to 1000 μm, such as greater than or equal to 400 μm and less than or equal to 800 μm, or greater than or equal to 400 μm and less than or equal to 800 μm. It should be understood that the thickness of the article may be within a sub-range formed from any and all of the foregoing endpoints.

(81) In embodiments, the glass compositions described herein may have a density in the range from greater than or equal to 2.20 to less than or equal to 2.60, from greater than or equal to 2.30 to less than or equal to 2.50, from greater than or equal to 2.30 to less than or equal to 2.45, from greater than or equal to 2.30 to less than or equal to 2.40, from greater than or equal to 2.30 to less than or equal to 2.35, from greater than or equal to 2.35 to less than or equal to 2.50, from greater than or equal to 2.35 to less than or equal to 2.45, from greater than or equal to 2.35 to less than or equal to 2.40, from greater than or equal to 2.40 to less than or equal to 2.50, from greater than or equal to 2.40 to less than or equal to 2.45, from greater than or equal to 2.45 to less than or equal to 2.50, or any and all sub-ranges formed from any of these endpoints.

(82) In embodiments, the liquidus viscosity of the glass composition is in the range from greater than or equal to 5.0 kP to less than or equal to 175.0 kP, from greater than or equal to 5.0 kP to less than or equal to 150.0 kP, from greater than or equal to 5.0 kP to less than or equal to 125.0 kP, from greater than or equal to 5.0 kP to less than or equal to 100.0 kP, from greater than or equal to 5.0 kP to less than or equal to 75.0 kP, from greater than or equal to 5.0 kP to less than or equal to 50.0 kP, from greater than or equal to 5.0 kP to less than or equal to 25.0 kP, from greater than or equal to 25.0 kP to less than or equal to 175.0 kP, from greater than or equal to 25.0 kP to less than or equal to 150.0 kP, from greater than or equal to 25.0 kP to less than or equal to 150.0 kP, from greater than or equal to 25.0 kP to less than or equal to 125.0 kP, from greater than or equal to 25.0 kP to less than or equal to 100.0 kP, from greater than or equal to 25.0 kP to less than or equal to 75.0 kP, from greater than or equal to 25.0 kP to less than or equal to 50.0 kP, from greater than or equal to 50.0 kP to less than or equal to 175.0 kP, from greater than or equal to 50.0 kP to less than or equal to 150.0 kP, from greater than or equal to 50.0 kP to less than or equal to 125.0 kP, from greater than or equal to 50.0 kP to less than or equal to 100.0 kP, from greater than or equal to 50.0 kP to less than or equal to 75.0 kP, from greater than or equal to 75.0 kP to less than or equal to 175.0 kP, from greater than or equal to 75.0 kP to less than or equal to 150.0 kP, from greater than or equal to 75.0 kP to less than or equal to 125.0 kP, from greater than or equal to 75.0 kP to less than or equal to 100.0 kP, from greater than or equal to 80.0 kP to less than or equal to 100.0 kP, from greater than or equal to 90.0 kP to less than or equal to 100.0 kP, from greater than or equal to 75.0 kP to less than or equal to 95.0 kP, or any and all sub-ranges formed from any of these endpoints.

(83) The softening point of the glass composition is also affected by the addition of lithium to the glass composition. In embodiments, to obtain a desired softening point, the glass composition may satisfy the relationship Al.sub.2O.sub.3*(4.90)+B.sub.2O.sub.3*(−8.97)+P.sub.2O.sub.5*(−1.87)+Li.sub.2O*(−11.26)+Na.sub.2O*(−8.29)+K.sub.2O*(−11.39)+MgO*(−4.69)+CaO*(−7.16)+SrO*(−2.81)<−100. In embodiments, to obtain a desired softening point, the glass composition may satisfy the relationship Al.sub.2O.sub.3*(4.52)+B.sub.2O.sub.3*(−8.28)+P.sub.2O.sub.5*(−1.73)+Li.sub.2O*(−10.40)+Na.sub.2O*(−7.65)+K.sub.2O*(−10.52)+MgO*(−4.33)+CaO*(−6.61)+SrO*(−2.60)≤−100. In embodiments, to obtain a desired softening point, the glass composition may satisfy the relationship Al.sub.2O.sub.3*(4.20)+B.sub.2O.sub.3*(−7.69)+P.sub.2O.sub.5*(−1.61)+Li.sub.2O*(−9.66)+Na.sub.2O*(−7.11)+K.sub.2O*(−9.78)+MgO*(−4.03)+CaO*(−6.14)+SrO*(−2.41)≤−100. In embodiments, the softening point of the glass composition may be in the range from greater than or equal 650.0° C. to less than or equal to 950.0° C., from greater than or equal to 650.0° C. to less than or equal to 925.0° C., from greater than or equal to 650.0° C. to less than or equal to 905.0° C., from greater than or equal to 650.0° C. to less than or equal to 900.0° C., from greater than or equal to 650.0° C. to less than or equal to 850.0° C., from greater than or equal to 650.0° C. to less than or equal to 800.0° C., from greater than or equal to 650.0° C. to less than or equal to 750.0° C., from greater than or equal to 650.0° C. to less than or equal to 700.0° C., from greater than or equal to 650.0° C. to less than or equal to 690.0° C., from greater than or equal to 660.0° C. to less than or equal to 680.0° C., from greater than or equal to 675.0° C. to less than or equal to 700.0° C., from greater than or equal to 700.0° C. to less than or equal to 950.0° C., from greater than or equal to 750.0° C. to less than or equal to 925.0° C., from greater than or equal to 775.0° C. to less than or equal to 925.0° C., from greater than or equal to 790.0° C. to less than or equal to 910.0° C., from greater than or equal to 795.0° C. to less than or equal to 905.0° C., from greater than or equal to 800.0° C. to less than or equal to 905.0° C., from greater than or equal to 800.0° C. to less than or equal to 900.0° C., from greater than or equal to 800.0° C. to less than or equal to 875.0° C., from greater than or equal to 800.0° C. to less than or equal to 850.0° C., from greater than or equal to 800.0° C. to less than or equal to 825.0° C., from greater than or equal to 825.0° C. to less than or equal to 875.0° C., from greater than or equal to 825.0° C. to less than or equal to 850.0° C., from greater than or equal to 850.0° C. to less than or equal to 900.0° C., or any and all sub-ranges between the foregoing values. In embodiments, the softening point of the glass composition may be less than or equal to 950.0° C., less than or equal to 925.0° C., less than or equal to 900.0° C., less than or equal to 875.0° C., less than or equal to 860.0° C., less than or equal to 850.0° C., less than or equal to 825.0° C., less than or equal to 800.0° C., less than or equal to 750.0° C., less than or equal to 700.0° C., less than or equal to 675.0° C., or less than or equal to 650.0° C.

(84) Fracture toughness (K.sub.1C) represents the ability of a glass composition to resist fracture. Fracture toughness is measured on a non-strengthened glass article, such as measuring the K.sub.1C value prior to ion exchange (IOX) treatment of the glass article, thereby representing a feature of a glass substrate prior to IOX. The fracture toughness test methods described herein are not suitable for glasses that have been exposed to IOX treatment. The measurements on corresponding underlying glass substrates (without IOX treatment), nonetheless, provide valuable information about the IOX'd glass properties. The chevron notched short bar (CNSB) method utilized to measure the K.sub.1C value is disclosed in Reddy, K. P. R. et al, “Fracture Toughness Measurement of Glass and Ceramic Materials Using Chevron-Notched Specimens,” J. Am. Ceram. Soc., 71 [6], C-310-C-313 (1988) except that Y*.sub.m is calculated using equation 5 of Bubsey, R. T. et al., “Closed-Form Expressions for Crack-Mouth Displacement and Stress Intensity Factors for Chevron-Notched Short Bar and Short Rod Specimens Based on Experimental Compliance Measurements,” NASA Technical Memorandum 83796, pp. 1-30 (October 1992). Unless otherwise specified, all fracture toughness values were measured by chevron notched short bar (CNSB) method. In embodiments, the K.sub.1C fracture toughness of the glass composition as measured by a chevron notch short bar method may be greater than or equal to 0.70, greater than or equal to 0.71, greater than or equal to 0.72, greater than or equal to 0.73, greater than or equal to 0.74, greater than or equal to 0.75, greater than or equal to 0.76, greater than or equal to 0.77, greater than or equal to 0.78, greater than or equal to 0.79, or greater than or equal to 0.80. In embodiments, the K.sub.1C fracture toughness of the glass composition as measured by a chevron notch short bar method may be in the range of from greater than or equal to 0.70 to less than or equal to 0.80 or greater than or equal to 0.73 to less than or equal to 0.75. It should be understood that the fracture toughness may be within a sub-range formed from any and all of the foregoing endpoints.

(85) The critical strain energy release rate is a calculation of the fracture toughness (K.sub.1C) divided by the Yong's modulus, and can be a good indicator of the mechanical strength of the glass composition. In embodiments, to obtain the desired critical strain energy release rate, Gc (J/m.sup.2), the glass composition may satisfy the relationship Al.sub.2O.sub.3*(10.832)+B.sub.2O.sub.3*(10.334)+P.sub.2O.sub.5*(−13.761)+Li.sub.2O*(−3.135)+Na.sub.2O*(−7.213)+K.sub.2O*(−13.761)+MgO*(2.159)+CaO*(−4.518)+SrO*(−4.518)>100. In embodiments, to obtain the desired Gc, the glass composition may satisfy the relationship Al.sub.2O.sub.3*(9.762)+B.sub.2O.sub.3*(9.313)+P.sub.2O.sub.5*(12.402)+Li.sub.2O*(−2.825)+Na.sub.2O*(−6.501)+K.sub.2O*(12.402)+MgO*(1.946)+CaO*(−4.072)+SrO*(−4.072)>100. In embodiments, to obtain the desired Gc, the glass composition may satisfy the relationship Al.sub.2O.sub.3*(8.885)+B.sub.2O.sub.3*(8.477)+P.sub.2O.sub.5*(11.288)+Li.sub.2O*(−2.571)+Na.sub.2O*(−5.917)+K.sub.2O*(11.288)+MgO*(1.771)+CaO*(−3.706)+SrO*(−3.706)>100.

(86) From the above, glass compositions according to embodiments may be formed by any suitable method, such as slot forming, float forming, rolling processes, fusion forming processes, etc.

(87) The glass article may be characterized by the manner in which it is formed. For instance, the glass article may be characterized as float-formable (i.e., formed by a float process), down-drawable and, in particular, fusion-formable or slot-drawable (i.e., formed by a down draw process such as a fusion draw process or a slot draw process).

(88) In embodiments, the glass articles described herein may be formed by a down-draw process. Down-draw processes produce glass articles having a uniform thickness that possess relatively pristine surfaces. Because the average flexural strength of the glass article is controlled by the amount and size of surface flaws, a pristine surface that has had minimal contact has a higher initial strength. In addition, down drawn glass articles have a very flat, smooth surface that can be used in its final application without costly grinding and polishing.

(89) In embodiments, the glass articles may be described as fusion-formable (i.e., formable using a fusion draw process). The fusion process uses a drawing tank that has a channel for accepting molten glass raw material. The channel has weirs that are open at the top along the length of the channel on both sides of the channel. When the channel fills with molten material, the molten glass overflows the weirs. Due to gravity, the molten glass flows down the outside surfaces of the drawing tank as two flowing glass films. These outside surfaces of the drawing tank extend down and inwardly so that they join at an edge below the drawing tank. The two flowing glass films join at this edge to fuse and forma single flowing glass article. The fusion draw method offers the advantage that, because the two glass films flowing over the channel fuse together, neither of the outside surfaces of the resulting glass article comes in contact with any part of the apparatus. Thus, the surface properties of the fusion drawn glass article are not affected by such contact.

(90) In embodiments, the glass articles described herein may be formed by a slot draw process. The slot draw process is distinct from the fusion draw method. In slot draw processes, the molten raw material glass is provided to a drawing tank. The bottom of the drawing tank has an open slot with a nozzle that extends the length of the slot. The molten glass flows through the slot/nozzle and is drawn downward as a continuous glass article and into an annealing region.

(91) As mentioned above, in embodiments, the alkali aluminosilicate glass compositions may be strengthened, such as by ion exchange, making a glass that is damage resistant for applications such as, but not limited to, glass for display covers. With reference to FIG. 5, the glass has a first region under compressive stress (e.g., first and second compressive layers 120, 122 in FIG. 5) extending from the surface to a DOC of the glass and a second region (e.g., central region 130 in FIG. 5) under a tensile stress or CT extending from the DOC into the central or interior region of the glass. A first segment 120 extends from first surface 110 to a depth d.sub.1 and a second segment 122 extends from second surface 112 to a depth d.sub.2. Together, these segments define a compression or CS of glass 100.

(92) In embodiments, the CS of the glass composition may be in the range from greater than or equal to 450.0 MPa to less than or equal to 950.0 MPa, from greater than or equal to 450.0 MPa to less than or equal to 900.0 MPa, from greater than or equal to 450.0 MPa to less than or equal to 850.0 MPa, from greater than or equal to 450.0 MPa to less than or equal to 800.0 MPa, from greater than or equal to 450.0 MPa to less than or equal to 750.0 MPa, from greater than or equal to 450.0 MPa to less than or equal to 700.0 MPa, from greater than or equal to 450.0 MPa to less than or equal to 650.0 MPa, from greater than or equal to 450.0 MPa to less than or equal to 600.0 MPa, from greater than or equal to 450.0 MPa to less than or equal to 550.0 MPa, from greater than or equal to 500.0 MPa to less than or equal to 950.0 MPa, from greater than or equal to 500.0 MPa to less than or equal to 900.0 MPa, from greater than or equal to 500.0 MPa to less than or equal to 850.0 MPa, from greater than or equal to 500.0 MPa to less than or equal to 800.0 MPa, from greater than or equal to 500.0 MPa to less than or equal to 750.0 MPa, from greater than or equal to 500.0 MPa to less than or equal to 700.0 MPa, from greater than or equal to 500.0 MPa to less than or equal to 650.0 MPa, from greater than or equal to 500.0 MPa to less than or equal to 600.0 MPa, from greater than or equal to 550.0 MPa to less than or equal to 950.0 MPa, from greater than or equal to 550.0 MPa to less than or equal to 900.0 MPa, from greater than or equal to 550.0 MPa to less than or equal to 850.0 MPa, from greater than or equal to 550.0 MPa to less than or equal to 800.0 MPa, from greater than or equal to 550.0 MPa to less than or equal to 750.0 MPa, from greater than or equal to 550.0 MPa to less than or equal to 700.0 MPa, from greater than or equal to 550.0 MPa to less than or equal to 650.0 MPa, from greater than or equal to 600.0 MPa to less than or equal to 950.0 MPa, from greater than or equal to 600.0 MPa to less than or equal to 900.0 MPa, from greater than or equal to 600.0 MPa to less than or equal to 850.0 MPa, from greater than or equal to 600.0 MPa to less than or equal to 800.0 MPa, from greater than or equal to 600.0 MPa to less than or equal to 750.0 MPa, from greater than or equal to 600.0 MPa to less than or equal to 700.0 MPa, from greater than or equal to 650.0 MPa to less than or equal to 950.0 MPa, from greater than or equal to 650.0 MPa to less than or equal to 900.0 MPa, from greater than or equal to 650.0 MPa to less than or equal to 850.0 MPa, from greater than or equal to 650.0 MPa to less than or equal to 800.0 MPa, from greater than or equal to 650.0 MPa to less than or equal to 750.0 MPa, from greater than or equal to 700.0 MPa to less than or equal to 950.0 MPa, from greater than or equal to 700.0 MPa to less than or equal to 900.0 MPa, from greater than or equal to 700.0 MPa to less than or equal to 850.0 MPa, from greater than or equal to 700.0 MPa to less than or equal to 800.0 MPa, from greater than or equal to 750.0 MPa to less than or equal to 950.0 MPa, from greater than or equal to 750.0 MPa to less than or equal to 900.0 MPa, from greater than or equal to 750.0 MPa to less than or equal to 850.0 MPa, from greater than or equal to 800.0 MPa to less than or equal to 950.0 MPa, from greater than or equal to 800.0 MPa to less than or equal to 900.0 MPa, or from greater than or equal to 850.0 MPa to less than or equal to 950.0 MPa, or any and all sub-ranges between the foregoing values. In embodiments, the CS of the glass composition may be greater than or equal to 450.0 mPa, greater than or equal to 500.0 mPa, greater than or equal to 550.0 mPa, greater than or equal to 600.0 MPa, greater than or equal to 650.0 MPa, greater than or equal to 700.0 MPa, greater than or equal to 750.0 MPa, greater than or equal to 800.0 MPa, greater than or equal to 850.0 MPa, or greater than or equal to 900.0 MPa.

(93) In embodiments, to obtain a desired maximum CT, the glass composition may satisfy 0.95<Al.sub.2O.sub.3*(5.9)−B.sub.2O.sub.3*(3.8)−P.sub.2O.sub.5*(8.3)+Li.sub.2O*(8.5)−Na.sub.2O*(4.6)−K.sub.2O*(10)+(MgO+CaO+SrO+ZnO)*(1.8)<1.5. In embodiments, to obtain a desired maximum CT, the glass composition may satisfy the relationship Al.sub.2O.sub.3*(6.31)+B.sub.2O.sub.3*(−4.05)+P.sub.2O.sub.5*(−8.89)+Li.sub.2O*(9.11)+Na.sub.2O*(−4.90)+K.sub.2O*(−10.73)+MgO*(1.96)+CaO*(1.96)+SrO*(1.96)>100. In embodiments, to obtain a desired maximum CT, the glass composition may satisfy the relationship Al.sub.2O.sub.3*(5.99)+B.sub.2O.sub.3*(−3.85)+P.sub.2O.sub.5*(−8.44)+Li.sub.2O*(8.65)+Na.sub.2O*(−4.65)+K.sub.2O*(−10.18)+MgO*(1.86)+CaO*(1.86)+SrO*(1.86)>100. In embodiments, to obtain a desired maximum CT, the glass composition may satisfy the relationship Al.sub.2O.sub.3*(5.70)+B.sub.2O.sub.3*(−3.66)+P.sub.2O.sub.5*(−8.03)+Li.sub.2O*(8.23)+Na.sub.2O*(−4.43)+K.sub.2O*(−9.69)+MgO*(1.77)+CaO*(1.77)+SrO*(1.77)>100. In embodiments, the maximum CT of the glass composition may be in the range from greater than or equal to 20.0 MPa to less than or equal to 150.0 MPa, from greater than or equal to 25.0 MPa to less than or equal to 125.0 MPa, from greater than or equal to 50.0 MPa to less than or equal to 125.0 MPa, from greater than or equal to 60.0 MPa to less than or equal to 100.0 MPa, from greater than or equal to 70.0 MPa to less than or equal to 100.0 MPa, from greater than or equal to 80.0 MPa to less than or equal to 100.0 MPa, from greater than or equal to 90.0 MPa to less than or equal to 100.0 MPa, from greater than or equal to 60.0 MPa to less than or equal to 90.0 MPa, from greater than or equal to 70.0 MPa to less than or equal to 90.0 MPa, from greater than or equal to 80.0 MPa to less than or equal to 90.0 MPa, from greater than or equal to 60.0 MPa to less than or equal to 80.0 MPa, from greater than or equal to 70.0 MPa to less than or equal to 80.0 MPa, from greater than or equal to 60.0 MPa to less than or equal to 70.0 MPa, or any and all sub-ranges between the foregoing values. In embodiments, the maximum CT of the glass composition may be greater than or equal to 20.0 MPa, greater than or equal to 50.0 MPa, greater than or equal to 60.0 MPa, greater than or equal to 65.0 MPa, greater than or equal to 70.0 MPa, greater than or equal to 75.0 MPa, greater than or equal to 80.0 MPa, greater than or equal to 85.0 MPa, greater than or equal to 90.0 MPa, greater than or equal to 95.0 MPa, or greater than or equal to 100.0 MPa.

(94) In embodiments, the DOC of the glass compositions may in the range from greater than or equal to 0.13t to less than or equal to 0.30t where t is the thickness of the articles, from greater than or equal to 0.13t to less than or equal to 0.28t, from greater than or equal to 0.13t to less than or equal to 0.26t, from greater than or equal to 0.13t to less than or equal to 0.24t, from greater than or equal to 0.13t to less than or equal to 0.22t, from greater than or equal to 0.13t to less than or equal to 0.20t, from greater than or equal to 0.13t to less than or equal to 0.18t, from greater than or equal to 0.15t to less than or equal to 0.30t, from greater than or equal to 0.15t to less than or equal to 0.28t, from greater than or equal to 0.15t to less than or equal to 0.26t, from greater than or equal to 0.15t to less than or equal to 0.24t, from greater than or equal to 0.15t to less than or equal to 0.22t, from greater than or equal to 0.15t to less than or equal to 0.20t, from greater than or equal to 0.15t to less than or equal to 0.18t, or any and all sub-ranges between the foregoing values. In embodiments, the DOC of the glass compositions may be greater than or equal to 0.13t where t is the thickness of the articles, greater than or equal to 0.14t, greater than or equal to 0.15t, greater than or equal to 0.16t, greater than or equal to 0.17t, greater than or equal to 0.18t, greater than or equal to 0.19t, greater than or equal to 0.20t, greater than or equal to 0.21t, greater than or equal to 0.22t, greater than or equal to 0.23t, greater than or equal to 0.24t, greater than or equal to 0.25t, greater than or equal to 0.26t, greater than or equal to 0.27t, greater than or equal to 0.28t, greater than or equal to 0.29t, or greater than or equal to 0.30t.

(95) In embodiments, the DOL of the glass composition may be in the range from greater than or equal to 1.0 μm to less than or equal to 25.0 μm, from greater than or equal to 5.0 μm to less than or equal to 20.0 μm, from greater than or equal to 5.0 μm to less than or equal to 18.0 μm, from greater than or equal to 5.0 μm to less than or equal to 15.0 μm, from greater than or equal to 5.0 μm to less than or equal to 12.0 μm, from greater than or equal to 5.0 μm to less than or equal to 10.0 μm, from greater than or equal to 7.0 μm to less than or equal to 20.0 μm, from greater than or equal to 7.0 μm to less than or equal to 18.0 μm, from greater than or equal to 7.0 μm to less than or equal to 15.0 μm, from greater than or equal to 7.0 μm to less than or equal to 12.0 μm, from greater than or equal to 7.0 μm to less than or equal to 10.0 μm, from greater than or equal to 10.0 μm to less than or equal to 20.0 μm, from greater than or equal to 10.0 μm to less than or equal to 18.0 μm, from greater than or equal to 10.0 μm to less than or equal to 15.0 μm, from greater than or equal to 10.0 μm to less than or equal to 12.0 μm, from greater than or equal to 12.0 μm to less than or equal to 20.0 μm, from greater than or equal to 12.0 μm to less than or equal to 18.0 μm, from greater than or equal to 12.0 μm to less than or equal to 15.0 μm, from greater than or equal to 15.0 μm to less than or equal to 20.0 μm, from greater than or equal to 15.0 μm to less than or equal to 18.0 μm, or from greater than or equal to 18.0 μm to less than or equal to 20.0 μm, or any and all sub-ranges between the foregoing values. In embodiments, the DOL may be greater than or equal to 5.0 μm, greater than or equal to 7.0 μm, greater than or equal to 10.0 μm, greater than or equal to 12.0 μm, greater than or equal to 15.0 μm, greater than or equal to 18.0 μm, or greater than or equal to 25.0 μm.

(96) In embodiments, the glass composition may have a compressive stress of greater than or equal to 600.0 MPa, a maximum central tension of greater than or equal to 20.0 MPa, a depth of compression of greater than or equal to 0.15t where t is the thickness of the articles, and a depth of layer of greater than or equal to 5.0 μm. In embodiments, the glass composition may have a compressive stress of greater than or equal to 600.0 MPa, a maximum central tension of greater than or equal to 60.0 MPa, a depth of compression of greater than or equal to 0.18t, and a depth of layer of greater than or equal to 10.0 μm. In embodiments, the glass composition may have a compressive stress greater than or equal to 450.0 mPa, greater than or equal to 500.0 mPa, greater than or equal to 550.0 mPa, greater than or equal to 600.0 MPa, greater than or equal to 650.0 MPa, greater than or equal to 700.0 MPa, greater than or equal to 750.0 MPa, greater than or equal to 800.0 MPa, greater than or equal to 850.0 MPa, or greater than or equal to 900.0 MPa; a maximum central tension greater than or equal to 20.0 MPa, greater than or equal to 50.0 MPa, greater than or equal to 60.0 MPa, greater than or equal to 65.0 MPa, greater than or equal to 70.0 MPa, greater than or equal to 75.0 MPa, greater than or equal to 80.0 MPa, greater than or equal to 85.0 MPa, greater than or equal to 90.0 MPa, greater than or equal to 95.0 MPa, or greater than or equal to 100.0 MPa; a depth of compression of greater than or equal to 0.13t, greater than or equal to 0.14t, greater than or equal to 0.15t, greater than or equal to 0.16t, greater than or equal to 0.17t, greater than or equal to 0.18t, greater than or equal to 0.19t, greater than or equal to 0.20t, greater than or equal to 0.21t, greater than or equal to 0.22t, greater than or equal to 0.23t, greater than or equal to 0.24t, greater than or equal to 0.25t, greater than or equal to 0.26t, greater than or equal to 0.27t, greater than or equal to 0.28t, greater than or equal to 0.29t, or greater than or equal to 0.30t; and a DOL greater than or equal to 5.0 μm, greater than or equal to 7.0 μm, greater than or equal to 10.0 μm, greater than or equal to 12.0 μm, greater than or equal to 15.0 μm, greater than or equal to 18.0 μm, or greater than or equal to 25.0 μm.

(97) In embodiments, the glass composition may have high crack and scratch resistance, as indicated by a Knoop Scratch threshold of at least 6.0 N. In embodiments, the glass composition may have a Knoop Scratch threshold in the range of 6.0 N to 12.0 N. According to embodiments, the Knoop Scratch threshold may be from greater than ore equal to 6.0 N and less than or equal to 9.0 N, such as from greater than or equal to 6.0 N and less than or equal to 12.0 N, greater than or equal to 7.0 N and less than or equal to 12.0 N, greater than or equal to 7.0 N and less than or equal to 11.0 N, or greater than or equal to 7.0 N and less than or equal to 10.0 N. It should be understood that the Knoop Scratch threshold of the glass-ceramics may be within a sub-range formed from any and all of the foregoing endpoints.

(98) In embodiments, the glass composition may have a failure height of greater than or equal to 100.0 cm, greater than or equal to 110.0 cm, greater than or equal to 120.0 cm, greater than or equal to 130.0 cm, greater than or equal to 140.0 cm, greater than or equal to 150.0 cm, greater than or equal to 160.0 cm, greater than or equal to 170.0 cm, greater than or equal to 180.0 cm, greater than or equal to 190.0 cm, or greater than or equal to 200.0 cm as measured for an article having a thickness of 0.5 mm according to the Drop Test Method on 180 grit sandpaper. In embodiments, the glass composition may have a failure height in the range from greater than or equal to 100.0 cm to less than or equal to 200.0 cm, from greater than or equal to 120.0 cm to less than or equal to 180.0 cm, from greater than or equal to 140.0 cm to less than or equal to 160.0 cm, or from greater than or equal to 145.0 cm to less than or equal to 155.0 cm, as measured for an article having a thickness of 0.5 mm according to the Drop Test Method on 180 grit sandpaper. In embodiments, the glass composition may have a failure height of greater than or equal to 150.0 cm, greater than or equal to 160.0 cm, greater than or equal to 170.0 cm, greater than or equal to 180.0 cm, greater than or equal to 190.0 cm, or greater than or equal to 200.0 cm as measured for an article having a thickness of 0.6 mm according to the Drop Test Method on 180 grit sandpaper. In embodiments, the glass composition may have a failure height in the range from greater than or equal to 150.0 cm to less than or equal to 200.0 cm, from greater than or equal to 160.0 cm to less than or equal to 190.0 cm, from greater than or equal to 165.0 cm to less than or equal to 185.0 cm, or from greater than or equal to 170.0 cm to less than or equal to 180.0 cm, as measured for an article having a thickness of 0.6 mm according to the Drop Test Method on 180 grit sandpaper.

(99) In embodiments, the glass composition may have a retained strength of greater than or equal to 150.0 MPa, greater than or equal to 175.0 MPa, greater than or equal to 200.0 MPa, or greater than or equal to 225.0 MPa as measured for an article having a thickness of 600.0 μm after impact with 80 grit sandpaper with a force of 500.0 N. In embodiments, the glass composition may have a retained strength in the range from greater than or equal to 150.0 MPa to less than or equal to 250.0 MPa, greater than or equal to 175.0 MPa to less than or equal to 225.0 MPa, or from greater than or equal to 190.0 MPa to less than or equal to 210.0 MPa as measured for an article having a thickness of 600.0 μm after impact with 80 grit sandpaper with a force of 500.0 N. In embodiments, the glass composition may have a retained strength of greater than or equal to 150.0 MPa, greater than or equal to 175.0 MPa, greater than or equal to 200.0 MPa, greater than or equal to 225.0 MPa, or greater than or equal to 250.0 MPa as measured for an article having a thickness of 600.0 μm after impact with 120 grit sandpaper with a force of 500.0 N. In embodiments, the glass composition may have a retained strength in the range from greater than or equal to 150.0 MPa to less than or equal to 300.0 MPa, from greater than or equal to 175.0 MPa to less than or equal to 275.0 MPa, or from greater than or equal to 200.0 MPa to less than or equal to 250.0 MPa as measured for an article having a thickness of 600.0 μm after impact with 120 grit sandpaper with a force of 500.0 N. In embodiments, the glass composition may have a retained strength of greater than or equal to 200.0 MPa, greater than or equal to 225.0 MPa, greater than or equal to 250.0 MPa, or greater than or equal to 270.0 MPa as measured for an article having a thickness of 600.0 μm after impact with 180 grit sandpaper with a force of 500.0 N. In embodiments, the glass composition may have a retained strength in the range from greater than or equal to 200.0 MPa to less than or equal to 300.0 MPa, from greater than or equal to 225.0 MPa to less than or equal to 290.0 MPa, or from greater than or equal to 250.0 MPa to less than or equal to 270.0 MPa as measured for an article having a thickness of 600.0 μm after impact with 180 grit sandpaper with a force of 500.0 N.

(100) The glass composition may be exposed to the ion exchange solution (e.g., KNO.sub.3 and/or NaNO.sub.3 molten salt bath) by dipping a glass article made from the glass composition into a bath of the ion exchange solution, spraying the ion exchange solution onto a glass article made from the glass composition, or otherwise physically applying the ion exchange solution to a glass article made from the glass composition. Upon exposure to the glass composition, the ion exchange solution may, according to embodiments, be at a temperature in the range from greater than or equal to 350.0° C. to less than or equal to 500.0° C., from greater than or equal to 360.0° C. to less than or equal to 450.0° C., from greater than or equal to 370.0° C. to less than or equal to 440.0° C., from greater than or equal to 360.0° C. to less than or equal to 420.0° C., from greater than or equal to 370.0° C. to less than or equal to 400.0° C., from greater than or equal to 375.0° C. to less than or equal to 475.0° C., from greater than or equal to 400.0° C. to less than or equal to 500.0° C., from greater than or equal to 410.0° C. to less than or equal to 490.0° C., from greater than or equal to 420.0° C. to less than or equal to 480.0° C., from greater than or equal to 430.0° C. to less than or equal to 470.0° C., or from greater than or equal to 440.0° C. to less than or equal to 460.0° C., or any and all sub-ranges between the foregoing values. In embodiments, the glass composition may be exposed to the ion exchange solution for a duration from greater than or equal to 2 hours to less than or equal to 48 hours, from greater than or equal to 2 hours to less than or equal to 24 hours, from greater than or equal to 2 hours to less than or equal to 12 hours, from greater than or equal to 2 hours to less than or equal to 6 hours, from greater than or equal to 8 hours to less than or equal to 44 hours, from greater than or equal to 12 hours to less than or equal to 40 hours, from greater than or equal to 16 hours to less than or equal to 36 hours, from greater than or equal to 20 hours to less than or equal to 32 hours, or from greater than or equal to 24 hours to less than or equal to 28 hours, or any and all sub-ranges between the foregoing values. The glass compositions described herein may undergo a single ion exchange process, a double ion exchange process, or multiple ion exchange processes. The glass compositions described herein have similar properties after undergoing a single ion exchange process as conventional glass compositions that have undergone multiple ion exchange processes.

(101) The ion exchange process may be performed in an ion exchange solution under processing conditions that provide an improved compressive stress profile as disclosed, for example, in U.S. Patent Application Publication No. 2016/0102011, which is incorporated herein by reference in its entirety.

(102) After an ion exchange process is performed, it should be understood that a composition at the surface of a glass article may be different than the composition of the as-formed glass article (i.e., the glass article before it undergoes an ion exchange process). This results from one type of alkali metal ion in the as-formed glass, such as, for example Li.sup.+ or Na.sup.+, being replaced with larger alkali metal ions, such as, for example Na.sup.+ or K.sup.+, respectively. However, the glass composition at or near the center of the depth of the glass article will, in embodiments, still have the composition of the as-formed (non-ion exchanged) glass utilized to form the glass article.

(103) The glass articles disclosed herein may be incorporated into another article such as an article with a display (or display articles) (e.g., consumer electronics, including mobile phones, tablets, computers, navigation systems, and the like), architectural articles, transportation articles (e.g., automobiles, trains, aircraft, sea craft, etc.), appliance articles, or any article that requires some transparency, scratch-resistance, abrasion resistance or a combination thereof. An exemplary article incorporating any of the glass articles disclosed herein is shown in FIGS. 6A and 6B. Specifically, FIGS. 6A and 6B show a consumer electronic device 200 including a housing 202 having front 204, back 206, and side surfaces 208; electrical components (not shown) that are at least partially inside or entirely within the housing and including at least a controller, a memory, and a display 210 at or adjacent to the front surface of the housing; and a cover substrate 212 at or over the front surface of the housing such that it is over the display. In embodiments, a portion of the cover substrate 212 and/or a portion of housing 202 may include any of the glass articles disclosed herein.

Examples

(104) The embodiments of the glass compositions described herein will be further clarified by the following examples.

(105) Table 1 shows example and comparative glass compositions (in terms of mol %) and the respective properties of glass compositions. Glasses were formed having the compositions 1-115 and comparative compositions 1-16 listed in Table 1.

(106) Table 2 shows the CS, DOL, and CT of comparative glass compositions 1-4 and example glass compositions 1-10 and 100-102 after applying an ion exchange solution to glass articles made from the example glass compositions at a temperature of 380° C. for 2 hours. The ion exchange solution applied to comparative glass compositions 1 and 2 and example glass compositions 1-10 was a 80 wt % KNO.sub.3/20 wt % NaNO.sub.3 molten salt bath. The ion exchange solution applied to comparative glass compositions 3 and 4 and example glass compositions 100-102 was a 95 wt % KNO.sub.3/5 wt % NaNO.sub.3 molten salt bath.

(107) Table 3 shows the CS, DOL, and CT of comparative glass compositions 1 and 2 and example glass compositions 1-10 after applying an ion exchange solution to glass articles made from the example glass compositions at a temperature of 380° C. for 3 hours. The ion exchange solution applied to comparative glass compositions 1 and 2 and example glass compositions 1-10 was a 80 wt % KNO.sub.3/20 wt % NaNO.sub.3 molten salt bath.

(108) Table 4 shows the CS, DOL, and CT of comparative glass compositions 1-4 and example glass compositions 1-10 and 100-102 after applying an ion exchange solution to glass articles made from the example glass compositions at a temperature of 380° C. for 4 hours. The ion exchange solution applied to comparative glass compositions 1 and 2 and example glass compositions 1-10 was a 80 wt % KNO.sub.3/20 wt % NaNO.sub.3 molten salt bath. The ion exchange solution applied to comparative glass compositions 3 and 4 and example glass compositions 100-102 was a 95 wt % KNO.sub.3/5 wt % NaNO.sub.3 molten salt bath.

(109) Table 5 shows the CS, DOL, and CT of comparative glass compositions 3 and 4 and example glass compositions 100-102 after applying an ion exchange solution to glass articles made from the example glass compositions at a temperature of 380° C. for 6 hours. The ion exchange solution applied to comparative glass compositions 3 and 4 and example glass compositions 100-102 was a 95 wt % KNO.sub.3/5 wt % NaNO.sub.3 molten salt bath.

(110) Table 6 shows the CS, DOL, and CT of comparative glass compositions 5-16 and example glass compositions 29-34 and 37-99 after applying an ion exchange solution to glass articles made from the example glass compositions at a temperature of 430° C. for 4 hours. The ion exchange solution applied to comparative glass compositions 5-16 and example glass compositions 29-34 and 37-99 was a 80 wt % KNO.sub.3/20 wt % NaNO.sub.3 molten salt bath.

(111) Table 7 shows the CS, DOL, and CT of comparative glass compositions 5-16 and example glass compositions 29-34 and 37-99 after applying an ion exchange solution to glass articles made from the example glass compositions at a temperature of 430° C. for 8 hours. The ion exchange solution applied to comparative glass compositions 5-16 and example glass compositions 29-34 and 37-99 was a 80 wt % KNO.sub.3/20 wt % NaNO.sub.3 molten salt bath.

(112) Table 8 shows the CS, DOL, and CT of comparative glass compositions 5-16 and example glass compositions 29-34 and 37-99 after applying an ion exchange solution to glass articles made from the example glass compositions at a temperature of 430° C. for 12 hours. The respective properties were measured by testing glasses having a thickness of 0.8 mm. The ion exchange solution applied to comparative glass compositions 5-16 and example glass compositions 29-34 and 37-99 was a 80 wt % KNO.sub.3/20 wt % NaNO.sub.3 molten salt bath.

(113) TABLE-US-00001 TABLE 1 Example 1 2 3 4 5 6 7 8 SiO.sub.2 63.20 62.22 61.19 60.32 59.41 58.50 60.27 59.88 Al.sub.2O.sub.3 17.05 17.06 17.05 17.05 17.08 17.12 17.07 17.59 P.sub.2O.sub.5 2.42 2.45 2.46 2.43 2.44 2.43 2.46 2.42 B.sub.2O.sub.3 0.00 0.96 1.95 2.88 3.71 4.62 1.92 1.92 MgO 0.02 0.02 0.02 0.03 0.03 0.02 0.98 0.97 CaO 0.04 0.04 0.04 0.04 0.05 0.04 0.05 0.05 SrO 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 ZnO 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Li.sub.2O 8.89 8.85 8.88 8.85 8.87 8.84 8.86 8.80 Na.sub.2O 7.99 8.01 8.01 8.02 8.04 8.05 8.01 7.99 K.sub.2O 0.29 0.29 0.29 0.29 0.29 0.28 0.29 0.29 TiO.sub.2 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.01 SnO.sub.2 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Fe2O.sub.3 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 ZrO.sub.2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 RO 0.06 0.06 0.06 0.07 0.08 0.06 1.03 1.02 R.sub.2O 17.17 17.15 17.18 17.16 17.20 17.17 17.16 17.08 Al.sub.2O.sub.3 + R.sub.2O 34.22 34.21 34.23 34.21 34.28 34.29 34.23 34.67 Al.sub.2O.sub.3 + R.sub.2O + B.sub.2O.sub.3 34.22 35.17 36.18 37.09 37.99 38.91 36.15 36.59 (Al.sub.2O.sub.3 − (R.sub.2O + RO))/Li.sub.2O −0.02 −0.02 −0.02 −0.02 −0.02 −0.01 −0.13 −0.06 (B.sub.2O.sub.3 + P.sub.2O.sub.5 + Al.sub.2O.sub.3)/SiO.sub.2 0.31 0.33 0.35 0.37 0.39 0.41 0.36 0.37 Density (g/cm.sup.3) 2.406 2.404 2.4 2.397 2.392 2.388 2.409 2.411 CTE (ppm)(fiber) — — — — — — — — Strain Pt. (fiber) — — — — — — — — Anneal Pt. (fiber) — — — — — — — — Softening Pt. (fiber) — — — — — — — — 10{circumflex over ( )}11 Poises — — — — — — — — Strain Pt. (° C.) 600.5 579.3 559.4 541.9 533.2 521.7 545.6 553.5 Anneal Pt. (° C.) 651.4 629.6 609.9 592.2 583.1 570.1 594.7 602.8 Softening Pt. (° C.) 903.6 877.4 856.5 836.8 821.5 805.2 838.4 844.6 CTE at 500° C. cooling (ppm) — — — — — — — — CTE at 300° C. cooling (ppm) — — — — — — — — CTE at 50° C. cooling (ppm — — — — — — — — Fulchers A −3.707 −3.639 −3.502 −3.151 −3.197 −3.499 −3.132 −3.62 Fulchers B 9331.9 9235.9 8676.1 8489.8 8112 8653.7 7883 8840 Fulchers To 70.4 50.6 79.6 −1.0 67.6 24.0 103.3 54.6 200 P Temperature (° C.) 1624 1605 1575 1556 1543 1516 1554 1548 35000 P Temperature (° C.) 1201 1179 1158 1102 1116 1100 1130 1137 200000 P Temperature (° C.) 1106 1084 1065 1003 1022 1007 1038 1046 Liquidus Viscosity (kP) 95 91 83 50 86 86 55 69 K.sub.1C (CN) — — — — — — — — Standard Deviation (CN) — — — — — — — — SOC (nm/mm/MPa) 2.93 2.963 3.007 3.03 3.08 3.091 2.964 2.964 Refractive index 1.5064 1.5066 1.5068 1.5067 1.5068 1.5068 1.5088 1.5092 Young's Modulus (GPa) 77.99 77.10 76.34 75.51 74.62 73.59 77.3 77.7 Shear modulus (GPa) 32.1074 31.8318 31.4184 31.0739 30.5916 30.3849 31.8 31.9 Poisson's ratio 0.213 0.212 0.216 0.216 0.219 0.211 0.218 0.218 Example 9 10 11 12 13 14 15 16 SiO.sub.2 59.32 58.75 59.99 59.71 59.44 59.21 59.04 58.70 Al.sub.2O.sub.3 18.05 18.54 17.27 17.53 17.79 18.01 18.28 18.52 P.sub.2O.sub.5 2.44 2.44 2.43 2.45 2.46 2.45 2.43 2.44 B.sub.2O.sub.3 1.92 1.96 2.79 2.75 2.78 2.74 2.75 2.79 MgO 0.98 0.98 0.02 0.02 0.02 0.03 0.02 0.03 CaO 0.05 0.05 0.04 0.04 0.04 0.04 0.04 0.04 SrO 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 ZnO 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Li.sub.2O 8.85 8.92 8.93 8.97 8.94 8.98 8.91 8.94 Na.sub.2O 8.00 7.97 8.18 8.17 8.17 8.20 8.19 8.19 K.sub.2O 0.29 0.29 0.27 0.27 0.27 0.27 0.27 0.27 TiO.sub.2 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 SnO.sub.2 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Fe2O.sub.3 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 ZrO.sub.2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 RO 1.03 1.03 0.06 0.06 0.06 0.07 0.06 0.07 R.sub.2O 17.14 17.18 17.38 17.41 17.38 17.45 17.37 17.40 Al.sub.2O.sub.3 + R.sub.2O 35.19 35.72 34.65 34.94 35.17 35.46 35.65 35.92 Al.sub.2O.sub.3 + R.sub.2O + B.sub.2O.sub.3 37.11 37.68 37.44 37.69 37.95 38.20 38.40 38.71 (Al.sub.2O.sub.3 − (R.sub.2O + RO))/Li.sub.2O −0.01 0.04 −0.02 0.01 0.04 0.05 0.10 0.12 (B.sub.2O.sub.3 + P.sub.2O.sub.5 + Al.sub.2O.sub.3)/SiO.sub.2 0.38 0.39 0.37 0.38 0.39 0.39 0.40 0.40 Density (g/cm.sup.3) 2.413 2.415 2.398 2.399 2.400 2.401 2.402 2.403 CTE (ppm)(fiber) — — — — — — — — Strain Pt. (fiber) — — — — — — — — Anneal Pt. (fiber) — — — — — — — — Softening Pt. (fiber) — — — — — — — — 10{circumflex over ( )}11 Poises — — — — — — — — Strain Pt. (° C.) 562.2 568.9 550.6 554.2 559 560.3 561.7 563.7 Anneal Pt. (° C.) 611.3 617.9 600.6 603.5 608.3 610.4 611 613.1 Softening Pt. (° C.) 849.2 853.2 838.2 840.4 843.5 848.3 848.2 850.7 CTE at 500° C. cooling (ppm) — — 8.49 8.43 8.31 8.35 8.20 8.24 CTE at 300° C. cooling (ppm) — — 7.93 7.84 7.77 7.82 7.65 7.72 CTE at 50° C. cooling (ppm — — 6.82 6.77 6.81 6.82 6.65 6.78 Fulchers A −3.462 −3.352 −2.976 −3.169 −3.485 −3.269 −3.086 −2.881 Fulchers B 8462.7 8127.1 7499.5 7935.7 8620 8099 7556.7 7017.6 Fulchers To 78.6 108.8 129 99.6 59.2 97.3 143.1 186.1 200 P Temperature (° C.) 1547 1546 1550 1550 1549 1551 1546 1540 35000 P Temperature (° C.) 1136 1138 1126 1128 1133 1134 1133 1131 200000 P Temperature (° C.) 1044 1048 1035 1037 1040 1042 1044 1044 Liquidus Viscosity (kP) 67 77 163 284 276 260 105 93 K.sub.1C (CN) — — — — — — — — Standard Deviation (CN) — — — — — — — — SOC (nm/mm/MPa) 2.972 2.948 3.025 3.043 3.039 3.042 3.036 3.031 Refractive index 1.5096 1.5104 1.5070 1.5073 1.5075 1.5076 1.5079 1.5083 Young's Modulus (GPa) 78.0 77.9 75.6 75.6 75.5 76.2 76.1 76.4 Shear modulus (GPa) 32.0 32.0 31.2 31.2 31.2 31.2 31.2 31.4 Poisson's ratio 0.22 0.219 0.213 0.212 0.211 0.220 0.219 0.218 Example 17 18 19 20 21 22 23 24 SiO.sub.2 60.04 59.58 59.39 59.18 59.09 58.71 59.17 58.75 Al.sub.2O.sub.3 17.29 17.52 17.75 18.01 18.33 18.50 17.50 17.52 P.sub.2O.sub.5 1.94 1.98 1.96 1.97 1.97 1.97 2.47 2.46 B.sub.2O.sub.3 3.23 3.38 3.28 3.35 3.16 3.22 2.81 2.78 MgO 0.02 0.02 0.04 0.03 0.03 0.03 0.02 0.03 CaO 0.04 0.04 0.05 0.04 0.04 0.04 0.04 0.05 SrO 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 ZnO 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Li.sub.2O 8.92 8.97 8.99 8.93 8.89 9.00 8.95 8.94 Na.sub.2O 8.17 8.17 8.19 8.15 8.15 8.19 8.20 8.15 K.sub.2O 0.26 0.26 0.27 0.26 0.26 0.27 0.27 0.26 TiO.sub.2 0.01 0.01 0.01 0.01 0.01 0.01 0.50 0.99 SnO.sub.2 0.05 0.06 0.05 0.06 0.05 0.05 0.06 0.05 Fe2O.sub.3 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 ZrO.sub.2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 RO 0.06 0.06 0.09 0.07 0.07 0.07 0.06 0.08 R.sub.2O 17.35 17.40 17.45 17.34 17.30 17.46 17.42 17.35 Al.sub.2O.sub.3 + R.sub.2O 34.64 34.92 35.20 35.35 35.63 35.96 34.92 34.87 Al.sub.2O.sub.3 + R.sub.2O + B.sub.2O.sub.3 37.87 38.30 38.48 38.70 38.79 39.18 37.73 37.65 (Al.sub.2O.sub.3 − (R.sub.2O + RO))/Li.sub.2O −0.01 0.01 0.02 0.07 0.11 0.11 0.00 0.01 B.sub.2O.sub.3 + P.sub.2O.sub.5 + Al.sub.2O.sub.3)/SiO.sub.2 0.37 0.38 0.39 0.39 0.40 0.40 0.38 0.39 Density (g/cm.sup.3) 2.398 2.399 2.400 2.401 2.402 2.403 2.404 2.408 CTE (ppm)(fiber) — — — — — — — — Strain Pt. (fiber) — — — — — — — — Anneal Pt. (fiber) — — — — — — — — Softening Pt. (fiber) — — — — — — — — 10{circumflex over ( )}11 Poises — — — — — — — — Strain Pt. (° C.) 545.4 548.6 555.5 555.5 564.3 565.3 547.4 543.1 Anneal Pt. (° C.) 595.2 598.2 605.3 605.9 613.8 614.6 596.5 592 Softening Pt. (° C.) 835.0 833.5 838.6 842.8 848.0 847.8 833.5 828.0 CTE at 500° C. cooling (ppm) — — — — — — 8.37 8.37 CTE at 300° C. cooling (ppm) 7.77 7.81 7.79 7.77 7.77 7.72 7.87 7.83 CTE at 50° C. cooling (ppm 6.86 6.91 6.90 6.87 6.87 6.83 6.92 6.91 Fulchers A −3.025 −3.09 −3.201 −4.203 −3.347 −2.797 −3.306 −3.298 Fulchers B 7672.8 7651.2 7943.9 10209 8134.8 6852.3 8199 8055.6 Fulchers To 109.4 118.3 96 −42 97.9 189.3 81.6 82 200 P Temperature (° C.) 1550 1538 1540 1528 1538 1533 1544 1521 35000 P Temperature (° C.) 1123 1121 1122 1125 1129 1123 1126 1109 200000 P Temperature (° C.) 1031 1030 1030 1032 1039 1035 1034 1019 Liquidus Viscosity (kP) 101 108 148 115 194 79 98 79 K.sub.1C (CN) — — — — — — — — Standard Deviation (CN) — — — — — — — — SOC (nm/mm/MPa) 3.045 3.044 3.026 3.027 3.030 3.039 3.064 3.098 Refractive index 1.5079 1.5081 1.5085 1.5087 1.5091 1.5096 1.5103 1.5128 Young's Modulus (GPa) 75.8 75.6 75.5 76.2 76.3 76.4 75.4 75.4 Shear modulus (GPa) 31.1 31.0 31.2 31.2 31.3 31.4 31.0 31.0 Poisson's ratio 0.22 0.218 0.212 0.22 0.219 0.218 0.217 0.214 Example 25 26 27 28 29 30 31 32 SiO.sub.2 58.28 58.69 58.23 57.81 62.26 62.30 62.24 62.26 Al.sub.2O.sub.3 17.53 18.00 18.01 18.00 15.09 15.09 16.09 15.10 P.sub.2O.sub.5 2.45 2.47 2.46 2.43 0.49 0.49 0.49 0.49 B.sub.2O.sub.3 2.78 2.84 2.84 2.82 6.08 6.08 6.14 6.59 MgO 0.03 0.03 0.03 0.03 2.02 1.02 1.02 1.04 CaO 0.05 0.04 0.05 0.04 1.22 2.20 1.21 1.23 SrO 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 ZnO 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Li.sub.2O 8.93 8.95 8.92 8.89 6.91 6.94 6.88 7.45 Na.sub.2O 8.15 8.16 8.14 8.15 5.66 5.61 5.66 5.58 K.sub.2O 0.26 0.26 0.26 0.27 0.22 0.21 0.22 0.21 TiO.sub.2 1.48 0.50 0.99 1.48 0.00 0.00 0.00 0.00 SnO.sub.2 0.05 0.05 0.06 0.05 0.05 0.06 0.05 0.05 Fe2O.sub.3 0.02 0.02 0.02 0.02 0.01 0.01 0.01 0.01 ZrO.sub.2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 RO 0.08 0.07 0.08 0.07 3.24 3.22 2.23 2.27 R.sub.2O 17.34 17.37 17.32 17.31 12.79 12.76 12.76 13.24 Al.sub.2O.sub.3 + R.sub.2O 34.87 35.37 35.33 35.31 27.88 27.85 28.85 28.34 Al.sub.2O.sub.3 + R.sub.2O + B.sub.2O.sub.3 37.65 38.21 38.17 38.13 33.96 33.93 34.99 34.93 (Al.sub.2O.sub.3 − (R.sub.2O + RO))/Li.sub.2O 0.01 0.06 0.07 0.07 −0.14 −0.13 0.16 −0.06 B.sub.2O.sub.3 + P.sub.2O.sub.5 + Al.sub.2O.sub.3)/SiO.sub.2 0.39 0.40 0.40 0.40 0.35 0.35 0.37 0.36 Density (g/cm.sup.3) 2.413 2.405 2.409 2.414 2.389 2.394 2.385 2.380 CTE (ppm)(fiber) — — — — 5.99 6.24 5.93 6.19 Strain Pt. (fiber) — — — — 541.0 541.0 559.0 535.0 Anneal Pt. (fiber) — — — — 587.0 586.0 608.0 583.0 Softening Pt. (fiber) — — — — 820.5 816.3 845.7 817.1 10{circumflex over ( )}11 Poises — — — — 664 664 689 663 Strain Pt. (° C.) 541.2 553.4 550.9 547.1 — — — — Anneal Pt. (° C.) 588.9 602.9 600.3 595.3 — — — — Softening Pt. (° C.) 820.4 838.2 832.6* 824.8 — — — — CTE at 500° C. cooling (ppm) 8.33 8.34 8.26 8.35 — — — — CTE at 300° C. cooling (ppm) 7.81 7.83 7.73 7.79 6.12 6.17 6.12 6.29 CTE at 50° C. cooling (ppm 6.75 6.89 6.79 6.80 5.26 5.36 5.29 5.39 Fulchers A −3.273 −3.12 −3.213 −3.538 −3.196 −3.196 −3.251 −3.267 Fulchers B 8016.7 7659.2 7844.3 8481.3 7977.5 7977.5 7950.8 8261.8 Fulchers To 76.2 126.2 101.3 57.2 82.5 82.5 114.3 53.7 200 P Temperature (° C.) 1514 1539 1524 1510 1534 1534 1546 1537 35000 P Temperature (° C.) 1102 1126 1113 1107 1113 1113 1134 1111 200000 P Temperature (° C.) 1011 1036 1023 1017 1021 1021 1044 1018 Liquidus Viscosity (kP) 100 81 58 62 102 112 59 61 K.sub.1C (CN) — — — — — — — — Standard Deviation (CN) — — — — — — — — SOC (nm/mm/MPa) 3.140 3.072 3.114 3.103 3.143 3.132 3.176 3.200 Refractive index 1.5156 1.5105 1.5132 1.5160 1.5098 1.5107 1.5090 1.5085 Young's Modulus (GPa) 75.6 75.7 75.6 75.6 76.5 76.1 75.8 75.0 Shear modulus (GPa) 31.2 31.2 31.2 31.2 31.3 31.2 31.0 30.7 Poisson's ratio 0.214 0.215 0.213 0.212 0.223 0.22 0.222 0.222 Example 33 34 35 36 37 38 39 40 SiO.sub.2 62.14 62.37 62.30 58.65 62.26 61.69 61.79 62.34 Al.sub.2O.sub.3 15.04 15.59 15.04 17.85 15.07 15.03 15.06 15.09 P.sub.2O.sub.5 0.49 0.49 0.98 1.47 0.98 0.97 0.97 0.49 B.sub.2O.sub.3 6.15 5.95 6.02 4.22 6.02 6.66 6.58 6.51 MgO 1.02 1.02 1.02 1.19 1.01 1.03 1.01 1.02 CaO 1.22 1.22 1.23 0.00 1.22 1.22 1.22 1.22 SrO 1.03 1.03 1.03 0.00 1.02 1.03 1.02 0.51 ZnO 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Li.sub.2O 7.49 7.92 7.46 7.70 7.95 7.47 7.96 7.41 Na.sub.2O 5.14 4.14 4.65 8.72 4.18 4.62 4.12 5.13 K.sub.2O 0.21 0.21 0.21 0.07 0.22 0.21 0.21 0.22 TiO.sub.2 0.00 0.00 0.00 0.10 0.00 0.00 0.00 0.00 SnO.sub.2 0.05 0.05 0.05 0.04 0.05 0.05 0.05 0.06 Fe2O.sub.3 0.01 0.01 0.01 0.00 0.01 0.01 0.01 0.01 ZrO.sub.2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 RO 3.27 3.27 3.28 1.19 3.25 3.28 3.25 2.75 R.sub.2O 12.84 12.27 12.32 16.49 12.35 12.30 12.29 12.76 Al.sub.2O.sub.3 + R.sub.2O 27.88 27.86 27.36 34.34 27.42 27.33 27.35 27.85 Al.sub.2O.sub.3 + R.sub.2O + B.sub.2O.sub.3 34.03 33.81 33.38 38.56 33.44 33.99 33.93 34.36 (Al.sub.2O.sub.3 − (R.sub.2O + RO))/Li.sub.2O −0.14 0.01 −0.08 0.02 −0.07 −0.07 −0.06 −0.06 B.sub.2O.sub.3 + P.sub.2O.sub.5 + Al.sub.2O.sub.3)/SiO.sub.2 0.35 0.35 0.35 0.40 0.35 0.37 0.37 0.35 Density (g/cm.sup.3) 2.408 2.405 2.400 2.401 2.399 2.398 2.397 2.390 CTE (ppm)(fiber) 6.10 5.80 5.91 7.25 5.85 5.93 5.85 6.02 Strain Pt. (fiber) 537.0 553.0 544.0 543.0 545.0 541.0 538.0 546.0 Anneal Pt. (fiber) 583.0 600.0 591.0 591.0 592.0 588.0 584.0 593.0 Softening Pt. (fiber) 812.9 830.5 825.8 827.2 822.4 819.3 814.3 824.1 10{circumflex over ( )}11 Poises 660 678 670 670 670 666 661 670 Strain Pt. (° C.) — — — — — — — — Anneal Pt. (° C.) — — — — — — — — Softening Pt. (° C.) — — — — — — — — CTE at 500° C. cooling (ppm) — — — — — — — — CTE at 300° C. cooling (ppm) 6.38 6.06 6.19 — 6.12 6.17 6.12 6.29 CTE at 50° C. cooling (ppm 5.52 5.22 5.33 — 5.26 5.36 5.29 5.39 Fulchers A −2.926 −2.735 −3.113 −3.372 −3.049 −2.815 −3.066 −2.983 Fulchers B 7488.9 6806.1 7800.8 8122.9 7690.0 7125.0 7609.2 7549.8 Fulchers To 104.3 177.8 101.7 75.3 100.5 133.1 103.8 103.1 200 P Temperature (° C.) 1537 1529 1543 1507 1538 1526 1522 1532 35000 P Temperature (° C.) 1107 1113 1120 1101 1113 1101 1104 1106 200000 P Temperature (° C.) 1015 1025 1029 1012 1021 1011 1013 1014 Liquidus Viscosity (kP) 56 34 60 137 44 62 49 51 K.sub.1C (CN) — — — — — — — — Standard Deviation (CN) — — — — — — — — SOC (nm/mm/MPa) 3.138 3.135 3.156 — 3.143 3.155 3.175 3.174 Refractive index 1.5116 1.5123 1.5102 1.5090 1.5110 1.5102 1.5108 1.5099 Young's Modulus (GPa) 76.8 77.2 75.8 — 76.5 75.4 76.0 75.8 Shear modulus (GPa) 31.2 31.4 31.0 — 31.2 30.8 31.0 30.9 Poisson's ratio 0.228 0.227 0.221 — 0.227 0.223 0.224 0.227 Example 41 42 43 44 45 46 47 48 SiO.sub.2 62.24 62.23 62.30 61.33 61.86 63.44 62.89 62.90 Al.sub.2O.sub.3 15.58 16.04 16.07 16.32 16.07 15.14 15.68 16.24 P.sub.2O.sub.5 0.49 0.97 0.97 1.00 0.97 0.50 0.50 0.49 B.sub.2O.sub.3 6.55 6.13 6.08 6.55 6.52 5.92 5.91 5.49 MgO 1.02 1.02 1.02 1.05 1.02 0.02 0.02 0.02 CaO 1.23 1.22 1.21 1.25 1.22 0.03 0.03 0.03 SrO 0.52 0.00 0.00 0.00 0.00 2.91 2.93 2.93 ZnO 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Li.sub.2O 7.94 7.50 7.91 7.51 7.91 6.72 6.67 6.60 Na.sub.2O 4.16 4.62 4.16 4.69 4.15 5.06 5.09 5.03 K.sub.2O 0.21 0.22 0.21 0.22 0.22 0.21 0.22 0.21 TiO.sub.2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 SnO.sub.2 0.05 0.05 0.05 0.07 0.05 0.04 0.05 0.04 Fe2O.sub.3 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 ZrO.sub.2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 RO 2.77 2.24 2.23 2.30 2.24 2.96 2.98 2.98 R.sub.2O 12.31 12.34 12.28 12.42 12.28 11.99 11.98 11.84 Al.sub.2O.sub.3 + R.sub.2O 27.89 28.38 28.35 28.74 28.35 27.13 27.66 28.08 Al.sub.2O.sub.3 + R.sub.2O + B.sub.2O.sub.3 34.44 34.51 34.43 35.29 34.87 33.05 33.57 33.57 (Al.sub.2O.sub.3 − (R.sub.2O + RO))/Li.sub.2O 0.06 0.19 0.20 0.21 0.20 0.03 0.11 0.22 B.sub.2O.sub.3 + P.sub.2O.sub.5 + Al.sub.2O.sub.3)/SiO.sub.2 0.36 0.37 0.37 0.39 0.38 0.34 0.35 0.35 Density (g/cm.sup.3) 2.388 2.379 2.376 2.376 2.375 2.433 2.434 2.437 CTE (ppm)(fiber) 5.69 5.59 5.60 5.62 5.61 6.16 6.14 6.08 Strain Pt. (fiber) 556.0 562.0 558.0 559.0 557.0 564.0 551.7 573.7 Anneal Pt. (fiber) 603.0 611.0 607.0 608.0 605.0 595.2 601.5 624.3 Softening Pt. (fiber) 834.3 850.3 844.4 843.6 839.3 830.2 838.3 857.0 10{circumflex over ( )}11 Poises 680 690 685 685 680 670 680 700 Strain Pt. (° C.) — — — — — — — — Anneal Pt. (° C.) — — — — — — — — Softening Pt. (° C.) — — — — — — — — CTE at 500° C. cooling (ppm) — — — — — — — — CTE at 300° C. cooling (ppm) 6.00 5.83 5.90 5.91 5.89 — — — CTE at 50° C. cooling (ppm 5.16 4.89 5.09 5.09 5.06 — — — Fulchers A −2.814 −3.042 −2.909 −2.964 −2.789 −3.144 −3.212 −3.472 Fulchers B 6877.5 7510.6 7082.9 7265.6 6806.1 8041.5 8007.3 8416.1 Fulchers To 176.8 141.8 168.7 158.2 187.8 85.3 102.5 86.1 200 P Temperature (° C.) 1521 1547 1528 1538 1525 1562 1555 1544 35000 P Temperature (° C.) 1111 1132 1119 1126 1116 1131 1135 1136 200000 P Temperature (° C.) 1024 1042 1031 1037 1029 1038 1043 1045 Liquidus Viscosity (kP) 36 28 20 21 23 30 25 23 K.sub.1C (CN) — — — — — — — — Standard Deviation (CN) — — — — — — — — SOC (nm/mm/MPa) 3.173 3.197 3.160 3.217 3.203 3.102 3.114 3.080 Refractive index 1.5106 1.5088 1.5080 1.5080 1.5087 1.5110 1.5116 1.5122 Young's Modulus (GPa) 76.5 76.1 76.1 75.7 75.7 75.5 74.3 76.0 Shear modulus (GPa) 31.2 31.0 31.0 30.8 31.0 30.9 30.3 31.0 Poisson's ratio 0.227 0.227 0.227 0.229 0.223 0.223 0.224 0.224 Example 49 50 51 52 53 54 55 56 SiO.sub.2 62.91 62.63 62.09 63.57 63.02 62.48 62.87 62.25 Al.sub.2O.sub.3 15.11 15.67 16.19 15.17 15.68 16.15 15.14 15.63 P.sub.2O.sub.5 1.00 0.98 1.00 0.49 0.50 0.49 1.00 1.00 B.sub.2O.sub.3 5.95 5.79 5.75 5.87 5.67 5.82 5.88 5.99 MgO 0.03 0.02 0.02 0.99 1.01 1.00 1.01 1.01 CaO 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 SrO 2.92 2.92 2.96 1.95 1.98 1.96 1.97 1.96 ZnO 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Li.sub.2O 6.70 6.65 6.62 6.67 6.76 6.74 6.72 6.77 Na.sub.2O 5.08 5.05 5.06 5.02 5.08 5.06 5.11 5.11 K.sub.2O 0.22 0.21 0.22 0.21 0.21 0.21 0.21 0.21 TiO.sub.2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 SnO.sub.2 0.04 0.04 0.05 0.04 0.05 0.05 0.05 0.04 Fe2O.sub.3 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 ZrO.sub.2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 RO 2.98 2.97 3.01 2.97 3.02 2.99 3.01 3.00 R.sub.2O 12.00 11.91 11.90 11.90 12.05 12.01 12.04 12.09 Al.sub.2O.sub.3 + R.sub.2O 27.11 27.58 28.09 27.07 27.73 28.16 27.18 27.72 Al.sub.2O.sub.3 + R.sub.2O + B.sub.2O.sub.3 33.06 33.37 33.84 32.94 33.40 33.98 33.06 33.71 (Al.sub.2O.sub.3 − (R.sub.2O + RO))/Li.sub.2O 0.02 0.12 0.19 0.04 0.09 0.17 0.01 0.08 B.sub.2O.sub.3 + P.sub.2O.sub.5 + Al.sub.2O.sub.3)/SiO.sub.2 0.35 0.36 0.37 0.34 0.35 0.36 0.35 0.36 Density (g/cm.sup.3) 2.430 2.432 2.434 2.414 2.416 2.420 2.411 2.414 CTE (ppm)(fiber) 6.19 6.20 6.01 6.00 5.93 5.95 5.97 6.01 Strain Pt. (fiber) 543.3 551.2 558.9 555.0 557.0 561.0 544.0 549.0 Anneal Pt. (fiber) 592.6 602.0 609.3 604.0 605.0 609.0 593.0 597.0 Softening Pt. (fiber) 828.5 844.6 845.1 839.4 843.8 848.5 833.4 838.0 10{circumflex over ( )}11 Poises 670 680 680 680 680 690 670 670 Strain Pt. (° C.) — — — — — — — — Anneal Pt. (° C.) — — — — — — — — Softening Pt. (° C.) — — — — — — — — CTE at 500° C. cooling (ppm) — — — — — — — — CTE at 300° C. cooling (ppm) — — — — — — — — CTE at 50° C. cooling (ppm — — — — — — — — Fulchers A −3.593 −3.602 −3.210 −3.009 −3.172 −3.136 −3.309 −3.186 Fulchers B 9076.8 8883.1 7844.4 7752.3 7818.2 7662.5 8351.7 7941.3 Fulchers To 11.4 43.2 119.8 76.1 115.0 130.4 64.4 101.0 200 P Temperature (° C.) 1551 1548 1543 1536 1543 1540 1553 1548 35000 P Temperature (° C.) 1127 1134 1131 1102 1128 1128 1128 1128 200000 P Temperature (° C.) 1032 1041 1041 1009 1038 1039 1034 1037 Liquidus Viscosity (kP) 43 41 36 40 58 37 146 84 K.sub.1C (CN) — — — — — — — — Standard Deviation (CN) — — — — — — — — SOC (nm/mm/MPa) 3.110 3.133 3.100 3.144 3.134 3.121 3.134 3.141 Refractive index 1.5099 1.5106 1.5111 1.5099 1.5106 1.5113 1.5090 1.5096 Young's Modulus (GPa) 74.5 74.8 75.4 75.7 75.8 76.3 75.1 75.4 Shear modulus (GPa) 30.4 30.5 30.7 30.9 31.0 31.1 30.8 30.8 Poisson's ratio 0.225 0.224 0.228 0.224 0.223 0.227 0.222 0.224 Example 57 58 59 60 61 62 63 64 SiO.sub.2 61.80 63.23 62.75 62.77 62.77 62.36 61.91 63.44 Al.sub.2O.sub.3 16.10 15.11 15.61 16.20 15.11 15.62 16.13 15.12 P.sub.2O.sub.5 1.00 0.50 0.50 0.49 1.00 0.99 0.99 0.49 B.sub.2O.sub.3 5.95 5.91 5.85 5.49 5.84 5.76 5.74 5.72 MgO 1.00 0.02 0.02 0.02 0.02 0.02 0.03 0.99 CaO 0.03 0.02 0.03 0.03 0.03 0.03 0.03 0.03 SrO 1.96 1.94 1.95 1.94 1.95 1.94 1.94 0.97 ZnO 0.00 0.96 0.97 0.95 0.97 0.96 0.96 0.96 Li.sub.2O 6.79 6.97 6.95 6.83 6.93 6.95 6.92 6.89 Na.sub.2O 5.10 5.07 5.10 5.03 5.11 5.10 5.09 5.12 K.sub.2O 0.21 0.21 0.21 0.20 0.21 0.22 0.21 0.21 TiO.sub.2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 SnO.sub.2 0.05 0.05 0.04 0.04 0.04 0.04 0.04 0.05 Fe2O.sub.3 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 ZrO.sub.2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 RO 2.99 2.94 2.97 2.94 2.97 2.95 2.96 2.95 R.sub.2O 12.10 12.25 12.26 12.06 12.25 12.27 12.22 12.22 Al.sub.2O.sub.3 + R.sub.2O 28.20 27.36 27.87 28.26 27.36 27.89 28.35 27.34 Al.sub.2O.sub.3 + R.sub.2O + B.sub.2O.sub.3 34.15 33.27 33.72 33.75 33.20 33.65 34.09 33.06 (Al.sub.2O.sub.3 − (R.sub.2O + RO))/Li.sub.2O 0.15 −0.01 0.05 0.18 −0.02 0.06 0.14 −0.01 B.sub.2O.sub.3 + P.sub.2O.sub.5 + Al.sub.2O.sub.3)/SiO.sub.2 0.37 0.34 0.35 0.35 0.35 0.36 0.37 0.34 Density (g/cm.sup.3) 2.417 2.426 2.429 2.433 2.424 2.426 2.430 2.410 CTE (ppm)(fiber) 5.87 — — — — — — 5.71 Strain Pt. (fiber) 553.0 — — — — — — — Anneal Pt. (fiber) 602.0 — — — — — — — Softening Pt. (fiber) 841.9 — — — — — — — 10{circumflex over ( )}11 Poises 680 — — — — — — — Strain Pt. (° C.) — 533.9 532.8 552.3 536 538.6 550.6 537.1 Anneal Pt. (° C.) — 583.3 593.1 602 584.4 588.9 600.8 586.4 Softening Pt. (° C.) — 827.4 831.9 842.6 827.9 829.9 836.7 832.8 CTE at 500° C. cooling (ppm) — — — — — — — — CTE at 300° C. cooling (ppm) — — — — — — — — CTE at 50° C. cooling (ppm — — — — — — — — Fulchers A −3.086 −3.451 −3.512 −2.985 −3.455 −3.072 −3.439 −3.557 Fulcher B 7621.4 8743.6 8737.4 7370.3 8772.2 7697.8 8419.2 8908.2 Fulchers To 127.6 31.7 45.5 147.9 23.1 111.1 70.9 27.3 200 P Temperature (° C.) 1542 1552 1549 1542 1547 1544 1538 1548 35000 P Temperature (° C.) 1126 1125 1130 1127 1120 1122 1126 1127 200000 P Temperature (° C.) 1036 1031 1037 1037 1025 1030 1034 1033 Liquidus Viscosity (kP) 91 16 14 13 41 26 20 16 K.sub.1C (CN) — — — — — — — — Standard Deviation (CN) — — — — — — — — SOC (nm/mm/MPa) 3.110 3.184 3.177 3.167 3.188 3.153 3.154 3.169 Refractive index 1.5105 1.5116 1.5115 1.5124 1.5100 1.5105 1.5116 1.5098 Young's Modulus (GPa) 75.6 75.4 75.4 76.1 74.9 75.0 75.5 76.1 Shear modulus (GPa) 30.8 30.8 30.8 31.0 30.6 30.6 31.0 31.0 Poisson's ratio 0.225 0.223 0.223 0.226 0.224 0.224 0.220 0.226 Example 65 66 67 68 69 70 71 72 SiO.sub.2 62.74 62.30 62.77 62.36 61.67 62.53 62.09 62.12 Al.sub.2O.sub.3 15.60 16.11 15.11 15.61 16.09 15.62 15.82 16.14 P.sub.2O.sub.5 0.49 0.50 0.99 0.98 0.99 0.50 0.50 0.49 B.sub.2O.sub.3 5.93 5.87 5.84 5.79 5.90 5.74 5.95 5.77 MgO 1.00 1.00 1.00 1.00 1.01 0.08 0.08 0.08 CaO 0.03 0.03 0.03 0.03 0.03 3.24 3.27 3.23 SrO 0.97 0.98 0.98 0.98 0.99 0.00 0.00 0.00 ZnO 0.96 0.96 0.97 0.96 0.98 0.00 0.00 0.00 Li.sub.2O 6.91 6.89 6.93 6.93 6.98 6.97 7.01 6.93 Na.sub.2O 5.09 5.11 5.12 5.09 5.10 5.04 5.01 4.99 K.sub.2O 0.21 0.21 0.21 0.21 0.21 0.22 0.21 0.21 TiO.sub.2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 SnO.sub.2 0.05 0.05 0.05 0.05 0.05 0.05 0.05 0.05 Fe2O.sub.3 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 ZrO.sub.2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 RO 2.96 2.97 2.98 2.97 3.01 3.32 3.35 3.31 R.sub.2O 12.21 12.21 12.26 12.23 12.29 12.23 12.23 12.13 Al.sub.2O.sub.3 + R.sub.2O 27.81 28.32 27.37 27.84 28.38 27.85 28.05 28.27 Al.sub.2O.sub.3 + R.sub.2O + B.sub.2O.sub.3 33.74 34.19 33.21 33.63 34.28 33.59 34.00 34.04 (Al.sub.2O.sub.3 − (R.sub.2O + RO))/Li.sub.2O 0.06 0.13 −0.02 0.06 0.11 0.01 0.03 0.10 B.sub.2O.sub.3 + P.sub.2O.sub.5 + Al.sub.2O.sub.3)/SiO.sub.2 0.35 0.36 0.35 0.36 0.37 0.35 0.36 0.36 Density (g/cm.sup.3) 2.413 2.417 2.407 2.410 2.413 2.396 2.397 2.399 CTE (ppm)(fiber) 5.68 5.67 5.85 5.70 5.64 5.94 6.00 5.95 Strain Pt. (fiber) — — — — — — — — Anneal Pt. (fiber) — — — — — — — — Softening Pt. (fiber) — — — — — — — — 10{circumflex over ( )}11 Poises — — — — — — — — Strain Pt. (° C.) 541.9 549.5 536.1 539.0 546.0 551.9 552.3 559.1 Anneal Pt. (° C.) 591.6 599.1 585.2 589.1 594.9 600.7 601.8 609.1 Softening Pt. (° C.) 832.3 841.6 829.0 829.8 833.0 835.0 835.6 837.7 CTE at 500° C. cooling (ppm) — — — — — — — — CTE at 300° C. cooling (ppm) — — — — — 6.19 6.08 6.14 CTE at 50° C. cooling (ppm — — — — — 5.53 5.36 5.5 Fulchers A −3.316 −3.012 −3.664 −3.447 −3.661 −3.213 −3.048 −3.151 Fulchers B 8164.3 7349.8 9129.5 8544.5 8922.5 7971.3 7478.2 7732.2 Fulchers To 85.7 144.0 14.7 55.2 36.9 84.8 121 120.7 200 P Temperature (° C.) 1539 1527 1545 1542 1533 1530 1519 1539 35000 P Temperature (° C.) 1124 1117 1127 1124 1124 1112 1106 1126 200000 P Temperature (° C.) 1033 1028 1033 1032 1032 1021 1017 1036 Liquidus Viscosity (kP) 13 8 19 10 12 48 36 56 K.sub.1C (CN) — — — — — — — — Standard Deviation (CN) — — — — — — — — SOC (nm/mm/MPa) 3.166 3.157 3.213 3.194 3.178 3.111 3.137 3.113 Refractive index 1.5105 1.5113 1.5087 1.5096 1.5104 1.5124 1.5121 1.5132 Young's Modulus (GPa) 76.7 76.7 75.4 75.7 76.0 76.5 76.6 76.7 Shear modulus (GPa) 31.2 31.4 30.8 31.0 31.1 31.2 31.3 31.2 Poisson's ratio 0.226 0.222 0.222 0.223 0.223 0.225 0.225 0.227 Example 73 74 75 76 77 78 79 80 SiO.sub.2 62.33 62.40 62.26 62.67 63.66 64.61 62.63 63.59 Al.sub.2O.sub.3 15.86 15.88 15.87 16.02 16.03 16.01 16.03 16.02 P.sub.2O.sub.5 0.49 0.49 0.49 0.50 0.49 0.50 0.50 0.50 B.sub.2O.sub.3 5.77 5.75 5.92 5.01 4.04 3.09 5.02 4.08 MgO 0.09 0.08 0.08 0.08 0.09 0.08 0.08 0.08 CaO 3.23 3.22 3.24 3.25 3.25 3.27 3.28 3.29 SrO 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 ZnO 0.00 0.00 0.00 0.01 0.01 0.01 0.01 0.01 Li.sub.2O 7.17 7.38 7.58 7.35 7.33 7.29 7.60 7.56 Na.sub.2O 4.79 4.54 4.29 4.83 4.82 4.85 4.58 4.58 K.sub.2O 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 TiO.sub.2 0.00 0.00 0.00 0.01 0.01 0.01 0.01 0.01 SnO.sub.2 0.05 0.04 0.05 0.05 0.05 0.05 0.05 0.06 Fe2O.sub.3 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 ZrO.sub.2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 RO 3.32 3.30 3.32 3.34 3.35 3.36 3.37 3.38 R.sub.2O 12.17 12.13 12.08 12.39 12.36 12.35 12.39 12.35 Al.sub.2O.sub.3 + R.sub.2O 28.03 28.01 27.95 28.41 28.39 28.36 28.42 28.37 Al.sub.2O.sub.3 + R.sub.2O + B.sub.2O.sub.3 33.80 33.76 33.87 33.42 32.43 31.45 33.44 32.45 (Al.sub.2O.sub.3 − (R.sub.2O + RO))/Li.sub.2O 0.05 0.06 0.06 0.04 0.04 0.04 0.04 0.04 B.sub.2O.sub.3 + P.sub.2O.sub.5 + Al.sub.2O.sub.3)/SiO.sub.2 0.35 0.35 0.36 0.34 0.32 0.30 0.34 0.32 Density (g/cm.sup.3) 2.397 2.396 2.396 2.402 2.407 2.410 2.401 2.406 CTE (ppm)(fiber) 5.84 5.90 5.84 — — — — — Strain Pt. (fiber) — — — — — — — — Anneal Pt. (fiber) — — — — — — — — Softening Pt. (fiber) — — — — — — — — 10{circumflex over ( )}11 Poises — — — — — — — — Strain Pt. (° C.) 556.6 556.0 559.3 570.3 579.7 591.9 570.7 579.6 Anneal Pt. (° C.) 605.4 605.4 608.3 619.5 629.5 642.5 619.5 629.1 Softening Pt. (° C.) 833.5 837.1 834.0 845.7 863.3 877.8 848.2 862.7 CTE at 500° C. cooling (ppm) — 6.62 6.51 — — — — — CTE at 300° C. cooling (ppm) 6.18 6.11 6.00 — — — — — CTE at 50° C. cooling (ppm 5.56 5.29 5.23 — — — — — Fulchers A −3.217 −2.706 −3.219 −3.361 −3.375 −3.230 −3.019 −2.946 Fulchers B 7909.5 6657.5 7819.8 8084.3 8299.3 8109.8 7298.5 7352.0 Fulchers To 100.3 198.9 103.0 110.0 105.5 129.0 164.9 163.1 200 P Temperature (° C.) 1534 1529 1520 1538 1568 1595 1537 1564 35000 P Temperature (° C.) 1119 1117 1110 1133 1154 1172 1130 1145 200000 P Temperature (° C.) 1029 1030 1021 1043 1062 1080 1042 1055 Liquidus Viscosity (kP) 65 53 38 58 53 52 67 42 K.sub.1C (CN) — — — — — — — — Standard Deviation (CN) — — — — — — — — SOC (nm/mm/MPa) 3.129 3.088 3.113 3.069 3.052 2.999 3.085 3.034 Refractive index 1.5129 1.5128 1.5131 1.5128 1.5128 1.5129 1.5130 1.5131 Young's Modulus (GPa) 76.9 76.8 77.2 77.2 78.1 79.0 77.4 78.2 Shear modulus (GPa) 31.4 31.4 31.5 31.7 32.2 32.7 31.9 32.1 Poisson's ratio 0.226 0.225 0.224 0.218 0.213 0.209 0.216 0.217 Example 81 82 83 84 85 86 87 88 SiO.sub.2 64.62 63.28 64.31 65.16 63.39 64.20 65.16 62.64 Al.sub.2O.sub.3 16.03 15.56 15.56 15.51 15.58 15.55 15.54 16.06 P.sub.2O.sub.5 0.49 0.48 0.49 0.48 0.49 0.50 0.50 0.99 B.sub.2O.sub.3 3.06 5.05 3.83 3.06 4.78 3.94 3.00 4.87 MgO 0.09 0.08 0.08 0.08 0.08 0.08 0.09 0.95 CaO 3.26 3.19 3.27 3.21 3.24 3.29 3.26 0.02 SrO 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2.03 ZnO 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Li.sub.2O 7.59 7.34 7.36 7.40 7.59 7.59 7.58 7.62 Na.sub.2O 4.58 4.75 4.81 4.83 4.57 4.58 4.60 4.55 K.sub.2O 0.21 0.20 0.21 0.21 0.21 0.21 0.21 0.21 TiO.sub.2 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 SnO.sub.2 0.05 0.05 0.05 0.05 0.04 0.05 0.05 0.05 Fe2O.sub.3 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.00 ZrO.sub.2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 RO 3.36 3.27 3.35 3.29 3.32 3.37 3.35 3.00 R.sub.2O 12.38 12.29 12.38 12.44 12.37 12.38 12.39 12.38 Al.sub.2O.sub.3 + R.sub.2O 28.41 27.85 27.94 27.95 27.95 27.93 27.93 28.44 Al.sub.2O.sub.3 + R.sub.2O + B.sub.2O.sub.3 31.47 32.90 31.77 31.01 32.73 31.87 30.93 33.31 (Al.sub.2O.sub.3 − (R.sub.2O + RO))/Li.sub.2O 0.04 0.00 −0.02 −0.03 −0.01 −0.03 −0.03 0.09 B.sub.2O.sub.3 + P.sub.2O.sub.5 + Al.sub.2O.sub.3)/SiO.sub.2 0.30 0.33 0.31 0.29 0.33 0.31 0.29 0.35 Density (g/cm.sup.3) 2.410 2.399 2.404 2.408 2.399 2.402 2.407 2.420 CTE (ppm)(fiber) — — — — — — — — Strain Pt. (fiber) — — — — — — — — Anneal Pt. (fiber) — — — — — — — — Softening Pt. (fiber) — — — — — — — — 10{circumflex over ( )}11 Poises — — — — — — — — Strain Pt. (° C.) 588.5 566.5 571.8 587.6 566.8 575.8 584.9 561.7 Anneal Pt. (° C.) 638.8 615.3 622.2 637.8 616.3 625.0 634.5 611.7 Softening Pt. (° C.) 878.7 841.6 856.5 872.7 843.1 858.0 872.4 849.4 CTE at 500° C. cooling (ppm) — — — — — — — — CTE at 300° C. cooling (ppm) — — — — — — — — CTE at 50° C. cooling (ppm — — — — — — — — Fulchers A −3.222 −3.144 −3.150 −3.160 −2.935 −3.109 −3.129 −3.194 Fulchers B 7976.4 7705.0 7988.2 7860.8 7367.5 7845.6 8000.4 7899.4 Fulchers To 142.8 129.5 115.8 145.7 140.2 124.4 125.6 123.5 200 P Temperature (° C.) 1587 1545 1581 1585 1547 1575 1599 1561 35000 P Temperature (° C.) 1170 1132 1154 1166 1125 1150 1168 1144 200000 P Temperature (° C.) 1079 1042 1061 1075 1035 1057 1075 1053 Liquidus Viscosity (kP) 42 52 49 51 38 59 52 65 K.sub.1C (CN) — — — — — — — — Standard Deviation (CN) — — — — — — — — SOC (nm/mm/MPa) 3.004 3.07 3.05 3.02 3.08 3.06 3.04 3.095 Refractive index 1.5131 1.5122 1.5125 1.5124 1.5125 1.5123 1.5126 1.5110 Young's Modulus (GPa) 79.5 77.3 78.5 79.0 77.4 78.2 79.2 76.80 Shear modulus (GPa) 32.6 31.7 32.0 32.5 31.6 32.1 32.4 31.40 Poisson's ratio 0.220 0.22 0.225 0.215 0.224 0.218 0.222 0.224 Example 89 90 91 92 93 94 95 96 SiO.sub.2 63.60 64.55 62.65 63.59 64.59 63.64 64.57 65.48 Al.sub.2O.sub.3 16.04 16.05 16.06 16.07 16.05 15.05 15.04 15.02 P.sub.2O.sub.5 0.98 0.99 0.99 0.99 0.98 0.99 0.99 0.98 B.sub.2O.sub.3 3.99 2.99 4.93 3.95 3.01 4.94 4.01 3.08 MgO 0.95 0.95 0.96 0.95 0.96 0.96 0.96 0.95 CaO 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 SrO 2.02 2.03 2.02 2.03 2.02 2.02 2.02 2.04 ZnO 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Li.sub.2O 7.60 7.58 7.81 7.79 7.79 7.55 7.57 7.61 Na.sub.2O 4.54 4.57 4.30 4.32 4.31 4.55 4.55 4.55 K.sub.2O 0.21 0.21 0.21 0.21 0.21 0.21 0.21 0.21 TiO.sub.2 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 SnO.sub.2 0.04 0.04 0.04 0.04 0.04 0.04 0.05 0.04 Fe2O.sub.3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 ZrO.sub.2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 RO 2.99 3.00 3.00 3.00 3.00 3.00 3.00 3.01 R.sub.2O 12.35 12.36 12.32 12.32 12.31 12.31 12.33 12.37 Al.sub.2O.sub.3 + R.sub.2O 28.39 28.41 28.38 28.39 28.36 27.36 27.37 27.39 Al.sub.2O.sub.3 + R.sub.2O + B.sub.2O.sub.3 32.38 31.40 33.31 32.34 31.37 32.30 31.38 30.47 (Al.sub.2O.sub.3 − (R.sub.2O + RO))/Li.sub.2O 0.09 0.09 0.09 0.10 0.09 −0.03 −0.04 −0.05 B.sub.2O.sub.3 + P.sub.2O.sub.5 + Al.sub.2O.sub.3)/SiO.sub.2 0.33 0.31 0.35 0.33 0.31 0.33 0.31 0.29 Density (g/cm.sup.3) 2.424 2.429 2.420 2.423 2.428 2.414 2.418 2.422 CTE (ppm)(fiber) — — — — — — — — Strain Pt. (fiber) — — — — — — — — Anneal Pt. (fiber) — — — — — — — — Softening Pt. (fiber) — — — — — — — — 10{circumflex over ( )}11 Poises — — — — — — — — Strain Pt. (° C.) 573.4 586.5 564.1 573.8 587.6 543.7 558.8 574.2 Anneal Pt. (° C.) 624.3 637.9 614.3 624.9 638.6 594.4 609.4 625.0 Softening Pt. (° C.) 864.9 884.5 852.2 868.0 880.5 837.5 857.2 873.7 CTE at 500° C. cooling (ppm) — — — — — — — — CTE at 300° C. cooling (ppm) — — — — — — — — CTE at 50° C. cooling (ppm — — — — — — — — Fulchers A −3.27 −3.411 −2.987 −3.219 −3.204 −3.106 −3.463 −3.414 Fulchers B 8145.8 8361.2 7358.5 7949.6 8043.9 7917.5 8839.2 8801.6 Fulchers To 117.2 117.3 155.5 131.8 136.9 100.7 57 73.1 200 P Temperature (° C.) 1579 1581 1547 1572 1598 1565 1591 1613 35000 P Temperature (° C.) 1160 1168 1133 1156 1175 1136 1161 1179 200000 P Temperature (° C.) 1068 1077 1043 1065 1083 1042 1066 1083 Liquidus Viscosity (kP) 59 53 48 51 42 60 65 57 K.sub.1C (CN) — — — — — — — — Standard Deviation (CN) — — — — — — — — SOC (nm/mm/MPa) 3.064 3.049 3.113 3.077 3.022 3.110 3.084 3.069 Refractive index 1.5108 1.5109 1.5113 1.5110 1.5113 1.5094 1.5097 1.5094 Young's Modulus (GPa) 76.80 78.60 77.00 77.70 78.70 76.3 76.9 77.9 Shear modulus (GPa) 31.40 32.20 31.40 31.90 32.30 31.2 31.5 32.0 Poisson's ratio 0.223 0.220 0.224 0.219 0.219 0.224 0.22 0.218 Example 97 98 99 100 101 102 103 104 SiO.sub.2 63.60 64.62 65.51 59.72 58.63 59.71 59.31 60.04 Al.sub.2O.sub.3 15.08 15.05 15.05 17.65 18.08 18.12 17.81 17.46 P.sub.2O.sub.5 1.00 0.99 0.99 0.00 0.48 0.49 1.90 1.78 B.sub.2O.sub.3 4.94 3.94 3.04 4.52 4.60 4.42 3.65 2.90 MgO 0.97 0.96 0.96 0.97 0.97 0.04 0.02 0.62 CaO 0.02 0.02 0.02 0.99 0.99 1.00 0.19 0.06 SrO 2.02 2.03 2.02 1.03 1.03 1.03 0.00 0.00 ZnO 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Li.sub.2O 7.81 7.84 7.83 6.89 6.46 6.94 8.74 8.53 Na.sub.2O 4.30 4.29 4.32 7.72 8.26 7.74 8.04 7.90 K.sub.2O 0.21 0.21 0.21 0.44 0.45 0.44 0.27 0.48 TiO.sub.2 0.01 0.01 0.01 0.01 0.00 0.01 0.00 0.17 SnO.sub.2 0.04 0.05 0.05 0.04 0.05 0.05 0.05 0.04 Fe2O.sub.3 0.00 0.00 0.00 0.01 0.01 0.01 0.02 0.02 ZrO.sub.2 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.01 RO 3.01 3.01 3.00 2.99 2.99 2.07 0.21 0.68 R.sub.2O 12.32 12.34 12.36 15.05 15.17 15.12 17.05 16.91 Al.sub.2O.sub.3 + R.sub.2O 27.40 27.39 27.41 32.70 33.25 33.24 34.86 34.37 Al.sub.2O.sub.3 + R.sub.2O + B.sub.2O.sub.3 32.34 31.33 30.45 37.22 37.85 37.66 38.51 37.27 (Al.sub.2O.sub.3 − (R.sub.2O + RO))/Li.sub.2O −0.03 −0.04 −0.04 −0.06 −0.01 0.13 0.06 −0.02 B.sub.2O.sub.3 + P.sub.2O.sub.5 + Al.sub.2O.sub.3)/SiO.sub.2 0.33 0.31 0.29 0.37 0.40 0.39 0.39 0.37 Density (g/cm.sup.3) 2.414 2.417 2.422 2.440 2.441 2.431 2.400 2.400 CTE (ppm)(fiber) — — — — — — 7.40 7.40 Strain Pt. (fiber) — — — — — — 546.0 550.0 Anneal Pt. (fiber) — — — — — — 596.0 599.0 Softening Pt. (fiber) — — — — — — 837.0 843.9 10{circumflex over ( )}11 Poises — — — 670 680 695 678 681 Strain Pt. (° C.) 548.5 559.0 573.9 547.2 555.6 569.5 543.4 546.8 Anneal Pt. (° C.) 598.4 609.5 624.6 595.1 604.2 619.1 592.9 597.1 Softening Pt. (° C.) 837.7 853.5 871.8 828.1 837.2 852.1 833.3 843.3 CTE at 500° C. cooling (ppm) — — — 7.85 7.90 7.71 8.28 8.21 CTE at 300° C. cooling (ppm) — — — 7.24 7.30 7.16 7.77 7.59 CTE at 50° C. cooling (ppm — — — 6.3 6.33 6.23 6.88 6.70 Fulchers A −3.139 −3.324 −3.224 −3.606 −2.981 −3.189 −3.263 −3.370 Fulchers B 7850.8 8461.5 8272.0 8640.4 7138.9 7658.2 8028.0 8309.0 Fulchers To 112 82.9 105.2 43.2 162 129.6 94.8 76.6 200 P Temperature (° C.) 1555 1587 1602 1506 1514 1525 1538 1542 35000 P Temperature (° C.) 1134 1158 1170 1103 1111 1120 1123 1127 200000 P Temperature (° C.) 1042 1064 1076 1013 1024 1032 1032 1035 Liquidus Viscosity (kP) 45 48 45 — — — 64 67 K.sub.1C (CN) — — — — — — 0.76 0.746 Standard Deviation (CN) — — — — — — 0.016 0.016 SOC (nm/mm/MPa) 3.104 3.099 3.063 2.984 2.990 3.037 3.05 3.03 Refractive index 1.5102 1.5096 1.5099 1.5157 1.5146 1.5133 1.5089 1.5097 Young's Modulus (GPa) 76.1 77.0 78.1 78.1 77.5 76.9 75.9 71.2 Shear modulus (GPa) 31.2 31.6 32.1 31.9 31.5 31.4 31.0 29.2 Poisson's ratio 0.22 0.217 0.218 0.225 0.229 0.225 0.223 0.219 Example 105 106 107 108 109 110 111 112 SiO.sub.2 58.89 57.75 62.08 62.36 62.50 58.49 58.72 59.16 Al.sub.2O.sub.3 17.35 18.03 16.27 15.66 15.20 18.02 18.22 17.90 P.sub.2O.sub.5 0.78 1.04 0.70 0.87 1.01 1.47 2.05 1.88 B.sub.2O.sub.3 4.56 4.73 5.02 5.47 5.86 4.22 3.12 3.61 MgO 1.76 1.70 0.07 0.58 0.96 1.19 1.06 0.03 CaO 0.29 0.05 3.07 1.46 0.23 0.04 0.13 0.16 SrO 0.72 0.97 0.01 1.08 1.86 0.00 0.00 0.00 ZnO 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Li.sub.2O 6.33 6.46 7.63 7.22 6.87 7.90 8.51 8.93 Na.sub.2O 8.95 8.99 4.69 4.86 5.06 8.52 7.86 7.99 K.sub.2O 0.13 0.05 0.21 0.21 0.22 0.07 0.27 0.26 TiO.sub.2 0.18 0.18 0.17 0.17 0.17 0.01 0.01 0.00 SnO.sub.2 0.04 0.03 0.05 0.04 0.05 0.05 0.05 0.06 Fe2O.sub.3 0.01 0.01 0.02 0.02 0.01 0.01 0.01 0.02 ZrO.sub.2 0.01 0.01 0.01 0.01 0.01 0.01 0.00 0.00 RO 2.77 2.72 3.15 3.12 3.05 1.23 1.19 0.19 R.sub.2O 15.41 15.50 12.53 12.29 12.15 16.49 16.64 17.18 Al.sub.2O.sub.3 + R.sub.2O 32.76 33.53 28.80 27.95 27.35 34.51 34.86 35.08 Al.sub.2O.sub.3 + R.sub.2O + B.sub.2O.sub.3 37.32 38.26 33.82 33.42 33.21 38.73 37.98 38.69 (Al.sub.2O.sub.3 − (R.sub.2O + RO))/Li.sub.2O −0.13 −0.03 0.08 0.03 0.00 0.04 0.05 0.06 B.sub.2O.sub.3 + P.sub.2O.sub.5 + Al.sub.2O.sub.3)/SiO.sub.2 0.39 0.41 0.35 0.35 0.35 0.41 0.40 0.40 Density (g/cm.sup.3) 2.424 2.428 2.397 2.402 2.406 2.401 2.42 2.40 CTE (ppm)(fiber) — 7.00 5.90 5.90 5.90 7.20 — — Strain Pt. (fiber) 542.0 549.0 561.0 549.0 539.0 547.0 — — Anneal Pt. (fiber) 589.0 596.0 610.0 598.0 588.0 596.0 — — Softening Pt. (fiber) 821.0 829.9 842.5 836.1 831.5 829.3 — — 10{circumflex over ( )}11 Poises 667 675 690 679 670 676 705 686 Strain Pt. (° C.) — 542.9 557.6 544.1 537.7 543.2 575.3 555.0 Anneal Pt. (° C.) — 591.8 606.8 593.2 587.2 592.0 624.3 604.2 Softening Pt. (° C.) — 825.5 839.2 832.3 823.4 827.9 858.8 843.8 CTE at 500° C. cooling (ppm) — 7.93 6.67 — 7.05 8.00 7.91 8.12 CTE at 300° C. cooling (ppm) — 7.28 6.15 — 6.38 7.36 7.44 7.60 CTE at 50° C. cooling (ppm — 6.47 5.44 — 5.56 6.50 6.62 6.77 Fulchers A −3.261 −3.262 −2.975 −3.274 −3.298 −3.263 −2.912 −3.213 Fulchers B 7924.5 7779.1 7211.6 8173.3 8317.3 7886.2 7076.6 7873.9 Fulchers To 89.4 99.9 158.0 77.6 59.2 94.8 185.4 108.4 200 P Temperature (° C.) 1514 1498 1525 1544 1545 1512 1543 1536 35000 P Temperature (° C.) 1105 1096 1117 1123 1120 1105 1135 1123 200000 P Temperature (° C.) 1015 1008 1029 1031 1026 1016 1047 1033 Liquidus Viscosity (kP) 162 43 44 83 152 89 29 59 K.sub.1C (CN) — 0.753 0.759 — 0.747 0.71 0.722 0.736 Standard Deviation (CN) — 0.006 0.01 — 0.005 0.007 0.022 0.024 SOC (nm/mm/MPa) — 3.01 3.05 3.10 3.15 3.05 2.98 3.02 Refractive index — 1.5136 1.5145 1.5117 1.5103 1.5106 1.5103 1.5092 Young's Modulus (GPa) — 77.1 78.3 — 75.6 76.9 78.3 76.4 Shear modulus (GPa) — 31.6 31.9 — 30.9 31.4 32.1 31.4 Poisson's ratio — 0.222 0.225 — 0.223 0.223 0.218 0.218 Comp. Comp. Example 113 114 115 1-4 5-16 SiO.sub.2 62.48 58.20 62.68 63.65 63.03 Al.sub.2O.sub.3 16.28 17.93 15.39 16.19 15.28 P.sub.2O.sub.5 0.71 1.03 0.96 2.67 0.02 B.sub.2O.sub.3 4.78 4.68 5.88 0.38 6.76 MgO 0.08 1.72 1.03 0.33 1.01 CaO 3.03 0.03 0.04 0.00 1.55 SrO 0.00 0.96 1.91 0.00 1.02 ZnO 0.00 0.00 0.00 0.00 0.00 Li.sub.2O 7.60 6.30 6.59 8.07 6.89 Na.sub.2O 4.77 9.05 5.28 8.11 4.35 K.sub.2O 0.21 0.03 0.18 0.52 0.03 TiO.sub.2 0.01 0.00 0.00 0.00 0.01 SnO.sub.2 0.05 0.06 0.05 0.05 0.04 Fe2O.sub.3 0.01 0.01 0.01 0.02 0.02 ZrO.sub.2 0.00 0.00 0.00 0.00 0.00 RO 3.11 2.71 2.98 0.33 3.58 R.sub.2O 12.58 15.38 12.05 16.70 11.27 Al.sub.2O.sub.3 + R.sub.2O 28.86 33.31 27.44 32.89 26.55 Al.sub.2O.sub.3 + R.sub.2O + B.sub.2O.sub.3 33.64 37.99 33.32 33.27 33.31 (Al.sub.2O.sub.3 − (R.sub.2O + RO))/Li.sub.2O 0.08 −0.03 0.05 −0.10 0.06 B.sub.2O.sub.3 + P.sub.2O.sub.5 + Al.sub.2O.sub.3)/SiO.sub.2 0.35 0.41 0.35 0.30 0.35 Density (g/cm.sup.3) 2.40 2.44 2.41 — — CTE (ppm)(fiber) — — — — — Strain Pt. (fiber) — — — — — Anneal Pt. (fiber) — — — — — Softening Pt. (fiber) — — — — — 10{circumflex over ( )}11 Poises 701 670 686 — — Strain Pt. (° C.) 571.1 544.3 551.7 — — Anneal Pt. (° C.) 620.5 591.9 602.4 — — Softening Pt. (° C.) 852.6 817.7 849.1 — — CTE at 500° C. cooling (ppm) 6.57 8.08 6.50 — — CTE at 300° C. cooling (ppm) 6.13 7.51 6.07 — — CTE at 50° C. cooling (ppm 5.39 6.57 5.47 — — Fulchers A −2.885 −3.110 −3.263 — — Fulchers B 7042.5 7431.6 8170.5 — — Fulchers To 188.6 117.6 85.7 — — 200 P Temperature (° C.) 1547 1491 1554 — — 35000 P Temperature (° C.) 1137 1089 1132 — — 200000 P Temperature (° C.) 1049 1001 1040 — — Liquidus Viscosity (kP) 77 120 109 — — K.sub.1C (CN) 0.776 0.74 0.754 — — Standard Deviation (CN) 0.014 0.051 0.018 — — SOC (nm/mm/MPa) 3.06 3.00 3.15 — — Refractive index 1.5128 1.5132 1.5091 — — Young's Modulus (GPa) 77.9 77.5 75.6 — — Shear modulus (GPa) 31.9 31.5 31.0 — — Poisson's ratio 0.220 0.229 0.221 — —

(114) TABLE-US-00002 TABLE 2 Example Comp. 1 Comp. 2 Comp. 3 Comp. 4 1 2 3 4 CS (MPa) 700 682 849 850 728 745 737 727 DOL (μm) 9.9 9.1 10.6 10.7 9.4 8.7 7.3 7.1 CT (MPa) 67.0 65.0 52.5 50.7 86.0 82.0 78.0 74.0 Example 5 6 7 8 9 10 100 101 CS (MPa) 707 703 — — — — — — DOL (μm) 6.9 6.7 — — — — — — CT (MPa) 68.0 64.0 70.0 69.0 72.0 71.0 38.2 36.0 Example 102 CS (MPa) — DOL (μm) — CT (MPa) 43.2

(115) TABLE-US-00003 TABLE 3 Example Comp. 1 Comp. 2 1 2 3 4 5 6 CS (MPa) 628 675 640 652 652 634 633 630 DOL (μm) 10.5 11.9 9.8 9.3 7.7 7.6 7.3 7.1 CT (MPa) 75.0 75.0 93.0 90.0 87.0 86.0 76.0 74.0 Example 7 8 9 10 CS (MPa) 718 726 738 749 DOL (μm) 6.9 6.8 6.5 6.4 CT (MPa) 83.0 83.0 85.0 83.0

(116) TABLE-US-00004 TABLE 4 Example Comp. 1 Comp. 2 Comp. 3 Comp. 4 1 2 3 4 CS (MPa) 614 667 843 835 626 649 649 623 DOL (μm) 12.4 12.6 15.1 13.8 10.9 10.3 9.7 9.4 CT (MPa) 79.0 77.0 59.1 56.1 97.0 97.0 93.0 90.0 Example 5 6 7 8 9 10 100 101 CS (MPa) 614 611 702 715 713 718 — 893 DOL (μm) 7.9 7.7 7.7 7.4 7.4 7.2 — 5.5 CT (MPa) 84.0 81.0 88.0 90.0 94.0 94.0 46.0 43.0 Example 102 CS (MPa) 870 DOL (μm) 6.0 CT (MPa) 52.7

(117) TABLE-US-00005 TABLE 5 Example Comp. 3 Comp. 4 100 101 102 CS (MPa) 835 828 892 886 848 DOL (μm) 18.5 17.8 6.0 6.4 7.8 CT (MPa) 58.6 56.1 55.9 54.0 64.9

(118) TABLE-US-00006 TABLE 6 Example Comp 5. Comp 6. Comp. 7 Comp. 8 Comp. 9 Comp. 10 Comp. 11 Comp. 12 CS (MPa) 599 — 571 584 588 590 582 582 DOL (μm) 6.4 — 6.5 6.4 6.7 6.4 6.4 6.4 CT (MPa) 77.4 76.7 76.7 83.0 79.9 77.6 77.6 78.0 Example Comp. 13 Comp. 14 Comp. 15 Comp. 16 29 30 31 32 CS (MPa) 594 588 588 587 572 586 576 569 DOL (μm) 6.3 6.4 6.3 6.3 10.2 9.7 10.4 11.7 CT (MPa) 78.2 79.2 79.6 78.2 79.1 73.9 78.7 74.5 Example 33 34 37 38 39 40 41 42 CS (MPa) 580 604 — — — 553 557 543 DOL (μm) 8.8 7.2 — — — 9.5 9.3 9.6 CT (MPa) 75.2 82.7 84.8 78.3 79.5 77.0 86.5 84.5 Example 43 44 45 46 47 48 49 50 CS (MPa) 550 537 538 573 576 584 564 570 DOL (μm) 9.2 9.5 8.4 9.2 8.3 7.8 9.7 9.4 CT (MPa) 90.3 81.5 86.4 75.1 77.6 86.9 72.2 74.0 Example 51 52 53 54 55 56 57 58 CS (MPa) 572 571 570 578 563 576 576 563 DOL (μm) 8.9 9.7 9.4 8.8 9.8 9.6 9.4 9.3 CT (MPa) 79.2 77.3 78.3 79.0 76.6 71.8 77.4 72.9 Example 59 60 61 62 63 64 65 66 CS (MPa) 573 571 549 557 567 561 552 573 DOL (μm) 7.9 9.1 9.4 9.4 8.9 9.1 9.4 8.9 CT (MPa) 76.0 72.7 70.6 74.5 74.2 78.0 75.1 78.0 Example 67 68 69 70 71 72 73 74 CS (MPa) 540 547 556 572 558 570 570 581 DOL (μm) 9.9 9.4 9.1 9.4 8.9 9.0 8.2 8.2 CT (MPa) 71.0 73.3 76.0 81.6 77.3 77.1 88.2 90.2 Example 75 76 77 78 79 80 81 82 CS (MPa) 578 589 580 606 600 600 612 590 DOL (μm) 8.3 7.7 7.7 7.5 7.8 7.7 7.7 8.0 CT (MPa) 91.4 94.8 102.8 100.4 97.0 104.2 102.8 94.5 Example 83 84 85 86 87 88 89 90 CS (MPa) 598 604 587 609 610 616 628 628 DOL (μm) 8.1 9.2 8.8 8.7 8.1 7.6 7.9 9.0 CT (MPa) 95.6 99.0 91.8 96.7 103.8 87.3 88.2 94.1 Example 91 92 93 94 95 96 97 98 CS (MPa) 619 636 621 575 580 581 567 576 DOL (μm) 7.5 7.6 7.9 9.4 9.7 10.0 9.2 9.3 CT (MPa) 87.6 97.3 100.2 85.3 89.6 90.2 91.3 94.3 Example 99 CS (MPa) 595 DOL (μm) 9.7 CT (MPa) 96.2

(119) TABLE-US-00007 TABLE 7 Example Comp. 5 Comp. 6 Comp. 7 Comp. 8 Comp. 9 Comp. 10 Comp. 11 Comp. 12 CS (MPa) 552 538 521 543 532 536 542 539 DOL (μm) 8.3 8.4 8.2 8.0 9.2 8.1 9.1 8.3 CT (MPa) 85.1 85.7 81.8 90.3 88.2 84.8 82.1 85.8 Example Comp. 13 Comp. 14 Comp. 15 Comp. 16 29 30 31 32 CS (MPa) 547 538 545 544 541 547 548 531 DOL (μm) 8.2 9.2 8.2 9.1 13.7 13.0 14.0 15.6 CT (MPa) 87.3 86.2 88.8 84.4 71.4 75.9 73.9 70.2 Example 33 34 37 38 39 40 41 42 CS (MPa) 544 557 527 527 525 514 522 510 DOL (μm) 11.6 10.7 11.3 11.5 11.0 13.4 11.1 13.2 CT (MPa) 76.9 94.9 91.1 78.7 85.5 74.1 88.7 79.0 Example 43 44 45 46 47 48 49 50 CS (MPa) 512 501 506 540 543 562 537 536 DOL (μm) 12.6 13.1 12.7 13.0 11.5 12.0 12.7 12.7 CT (MPa) 85.7 74.7 82.3 75.9 79.3 80.0 71.3 75.7 Example 51 52 53 54 55 56 57 58 CS (MPa) 544 530 552 549 525 541 545 532 DOL (μm) 12.5 13.1 12.9 12.4 13.4 13.5 12.9 12.8 CT (MPa) 84.1 73.8 76.6 80.0 71.0 78.1 76.2 70.2 Example 59 60 61 62 63 64 65 66 CS (MPa) 538 540 520 529 533 527 532 540 DOL (μm) 11.5 11.1 13.2 12.8 11.5 12.6 12.7 10.9 CT (MPa) 74.9 77.1 68.4 70.9 74.9 71.0 75.7 77.9 Example 67 68 69 70 71 72 73 74 CS (MPa) 510 501 527 533 534 540 534 544 DOL (μm) 13.3 13.1 11.5 11.1 12.1 11.0 11.0 10.7 CT (MPa) 68.6 66.0 71.0 78.6 80.3 81.0 85.0 87.9 Example 75 76 77 78 79 80 81 82 CS (MPa) 540 547 552 572 569 560 568 557 DOL (μm) 10.7 11.2 11.4 10.8 12.2 11.2 12.4 11.9 CT (MPa) 93.9 87.3 85.9 97.2 88.7 91.4 85.5 89.6 Example 83 84 85 86 87 88 89 90 CS (MPa) 555 558 558 577 567 578 590 597 DOL (μm) 12.5 12.8 11.8 11.8 12.4 11.2 12.6 13.0 CT (MPa) 84.8 84.3 93.1 94.6 88.7 89.9 89.1 86.2 Example 91 92 93 94 95 96 97 98 CS (MPa) 577 590 607 533 545 539 531 544 DOL (μm) 11.1 11.4 12.5 13.6 13.6 13.7 12.9 13.0 CT (MPa) 90.8 91.0 92.2 75.7 76.2 73.0 69.4 77.9 Example 99 CS (MPa) 554 DOL (μm) 13.4 CT (MPa) 80.6

(120) TABLE-US-00008 TABLE 8 Example Comp. 5 Comp. 6 Comp. 7 Comp. 8 Comp. 9 Comp. 10 Comp. 11 Comp. 12 CS (MPa) 523 527 496 515 512 513 513 513 DOL (μm) 10.6 10.6 10.8 10.6 10.8 10.6 10.6 10.7 CT (MPa) 78.6 76.6 — 80.7 80.7 78.6 76.3 78.3 Example Comp. 13 Comp. 14 Comp. 15 Comp. 16 29 30 31 32 CS (MPa) 512 512 513 525 515 526 514 503 DOL (μm) 10.8 10.8 10.8 10.8 16.7 16.7 16.9 19.4 CT (MPa) 78.1 79.2 79.4 75.9 59.7 65.8 60.7 57.5 Example 33 34 37 38 39 40 41 42 CS (MPa) 538 536 524 510 503 509 517 525 DOL (μm) 14.6 13.2 14.1 14.4 13.7 15.2 14.5 14.2 CT (MPa) 76.1 84.5 77.5 65.7 75.2 70.2 73.3 72.7 Example 43 44 45 46 47 48 49 50 CS (MPa) 483 475 474 509 517 525 506 521 DOL (μm) 14.6 16.2 14.6 15.2 14.5 14.2 14.8 14.7 CT (MPa) — — — 70.2 73.3 72.7 65.4 70.6 Example 51 52 53 54 55 56 57 58 CS (MPa) 520 509 521 518 503 513 522 506 DOL (μm) 14.5 16.3 15.8 14.1 16.8 16.1 16.1 14.7 CT (MPa) 64.1 63.9 68.5 72.2 63.1 67.9 66.1 63.5 Example 59 60 61 62 63 64 65 66 CS (MPa) 523 520 496 505 514 501 505 514 DOL (μm) 14.2 13.7 16.3 15.7 14.3 15.7 15.5 13.8 CT (MPa) 66.6 66.1 62.6 60.0 64.4 58.6 63.3 69.9 Example 67 68 69 70 71 72 73 74 CS (MPa) 484 488 498 506 501 512 504 519 DOL (μm) 16.3 15.9 14.4 14.1 14.0 13.8 13.3 13.7 CT (MPa) 57.5 58.2 63.1 68.2 69.1 69.2 75.6 75.0 Example 75 76 77 78 79 80 81 82 CS (MPa) 515 508 516 536 533 519 531 531 DOL (μm) 13.0 14.1 15.4 13.9 15.4 14.1 15.5 14.1 CT (MPa) 84.5 69.4 67.5 79.7 72.5 73.7 72.1 76.1 Example 83 84 85 86 87 88 89 90 CS (MPa) 528 534 529 547 535 542 554 560 DOL (μm) 14.5 16.2 14.0 14.5 15.4 14.3 15.8 16.2 CT (MPa) 73.2 68.2 77.9 82.2 72.7 74.6 75.9 70.1 Example 91 92 93 94 95 96 97 98 CS (MPa) 559 548 559 507 511 515 497 505 DOL (μm) 14.1 15.4 15.7 16.6 17.0 18.5 16.2 16.7 CT (MPa) 68.8 80.5 79.2 62.0 59.4 58.1 60.2 62.3 Example 99 CS (MPa) 523 DOL (μm) 16.8 CT (MPa) 62.4

(121) Table 9 shows the Knoop Scratch threshold data for glass articles made from example glass composition 110 and comparative example 1. As shown, glass articles made from example glass composition 110 has a higher Knoop Scratch threshold than comparative example 1.

(122) TABLE-US-00009 TABLE 9 Knoop Scratch Knoop Scratch Sample Threshold Per Threshold For Sample Number Sample (N) All Samples (N) Example 1 >10 ≤ 12 >9 ≤ 12 Composition 2 >10 ≤ 12 110 3  >9 ≤ 10 Comparative 1 >3 ≤ 4 >3 ≤ 5  Example 1 2 >3 ≤ 4 3 >4 ≤ 5

(123) FIG. 7 shows the average failure height of articles made from example glass composition 110 and articles made from comparative example 1 having a thickness of 0.5 mm and dropped on 180 grit sandpaper. As shown in FIG. 7, the articles made from example glass composition 110 had failure heights ranging from 50.0 cm to 100.0 cm with an average of 77.0 cm. The articles made from comparative example 1 had failure heights ranging from 35.0 cm to 65.0 cm with an average of 50.0 cm.

(124) FIG. 8 shows the average failure height of articles made from example glass composition 110 and articles made from comparative example 1 having a thickness of 0.6 mm and dropped on 180 grit sandpaper. As shown in FIG. 8, the articles made from example glass composition 110 had failure heights ranging from 125.0 cm to 175.0 cm with an average of 154.0 cm. The articles made from comparative example 1 had failure heights ranging from 60.0 cm to 125.0 cm with an average of 108.0 cm.

(125) FIG. 9 shows the retained strength of articles made from example glass composition 110 and articles made from comparative example 1. As shown in FIG. 9, the articles made from example glass composition 110 had retained strengths ranging from 175.0 MPa to 225.0 MPa when impacted with 80 grit sandpaper with a force of 500.0 N. The articles made from comparative example 1 had retained strengths ranging from 150.0 MPa to 170.0 MPa when impacted with 80 grit sandpaper with a force of 500.0 N. The articles made from example glass composition 110 had retained strengths ranging from 175.0 MPa to 275.0 MPa when impacted with 120 grit sandpaper with a force of 500.0 N. The articles made from comparative example 1 had retained strengths ranging from 170.0 MPa to 190.0 MPa when impacted with 120 grit sandpaper with a force of 500.0 N. The articles made from example glass composition 110 had retained strengths ranging from 250.0 MPa to 270.0 MPa when impacted with 180 grit sandpaper with a force of 500.0 N. The articles made from comparative example 1 had retained strengths ranging from 2000.0 MPa to 208.0 MPa when impacted with 180 grit sandpaper with a force of 500.0 N.

(126) It will be apparent to those skilled in the art that various modifications and variations can be made to the embodiments described herein without departing from the spirit and scope of the claimed subject matter. Thus it is intended that the specification cover the modifications and variations of the various embodiments described herein provided such modification and variations come within the scope of the appended claims and their equivalents.