An alkali free glass has an average coefficient of thermal expansion at 50 to 350 C. of 3010.sup.7 to 4310.sup.7/ C., a Young's modulus of 88 GPa or more, a strain point of 650 to 725 C., a temperature T.sub.4 at which a viscosity reaches 10.sup.4 dPa.Math.s of 1,290 C. or lower, a glass surface devitrification temperature (T.sub.c) of T.sub.4+20 C. or lower, and a temperature T.sub.2 at which the viscosity reaches 10.sup.2 dPa.Math.s of 1,680 C. or lower. The alkali free glass contains, as represented by mol % based on oxides, 62 to 67% of SiO.sub.2, 12.5 to 16.5% of Al.sub.2O.sub.3, 0 to 3% of B.sub.2O.sub.3, 8 to 13% of MgO, 6 to 12% of CaO, 0.5 to 4% of SrO, and 0 to 0.5% of BaO. MgO+CaO+SrO+BaO is 18 to 22%, and MgO/CaO is 0.8 to 1.33.

One aspect relates to a process for the preparation of a quartz glass body, including providing a silicon dioxide granulate, wherein the silicon dioxide granulate was made from pyrogenic silicon dioxide powder and the silicon dioxide granulate has a BET surface area in a range from 20 to 40 m.sup.2/g, making a glass melt out of silicon dioxide granulate in an oven and making a quartz glass body out of at least part of the glass melt. The oven has at least a first and a further chamber connected to one another via a passage. The temperature in the first chamber is lower than the temperature in the further chambers. On aspect relates to a quartz glass body which is obtainable by this process. One aspect relates to a light guide, an illuminant and a formed body, which are each obtainable by further processing of the quartz glass body.

Provided is a glass material that can satisfy both a high Faraday effect and a high light transmittance in a short wavelength range. A glass material contains, in % by mole, 30 to 50% Pr.sub.2O.sub.3 and 0.1 to 70% B.sub.2O.sub.3+P.sub.2O.sub.5.

A glass having a good hydrolytic resistance and alkali resistance is defined by a targeted combination of stoichiometric glasses, including glasses also existing as crystals in the same stoichiometry and whose properties can be assumed as being very similar due to the identical topology of the structural units for glass and crystal, respectively. A process of producing the glasses is also provided.

Described herein are alkali-free, boroalumino silicate glasses exhibiting desirable physical and chemical properties for use as substrates in flat panel display devices, such as, active matrix liquid crystal displays (AMLCDs) and active matrix organic light emitting diode displays (AMOLEDs). In accordance with certain of its aspects, the glasses possess good dimensional stability as a function of temperature.

The application relates to bond materials for a grinding wheel, in particular a glass ceramic and a preparation method thereof, and a bond for the composite grinding wheel. The glass ceramic is prepared from raw materials comprising kaolin, silica, diboron trioxide, lithium superoxide, albite, potassium feldspar, talc, dolomite, phosphorus pentoxide, and yttrium oxide. A glass ceramic composed entirely of microcrystalline phases is obtained from the glass prepared by the above raw materials at 900-1020 C., achieving a complete conversion of the glass phase at a low temperature. The application also provides a bond for a composite grinding wheel, comprising glass ceramic and glass with mass ratio of (20-50):(50-80), the glass phase having a low flow temperature and, together with the glass ceramic phase, forming encapsulation of the abrasive particles, realizing low-temperature sintering of the grinding wheel. Microcrystalline phase in the bond results in high mechanical strength for the obtained grinding wheel.

A composition comprising glass containing both trivalent cerium oxide and tetravalent cerium oxide states nano particles. A soluble sodium borate glass comprising cerium oxide that is stable against crystallizations, the cerium oxide comprising both trivalent Ce.sup.3+ (Ce.sub.2O.sub.3) and tetravalent Ce.sup.4+ (CeO.sub.2) states, wherein the cerium oxide nano particles are configured to be released when the glass is dissolved.

The present invention relates to an alkali-free glass and a method for producing the same. More specifically, the present invention relates to an alkali-free glass suitable as a glass for substrates of various displays such as liquid crystal display, and a method for producing the same. According to the present invention, an alkali-free glass suitable as a glass for display substrates, in which inclusion of bubbles is greatly reduced by virtue of containing a refining agent and suppressing the stirring reboil, is obtained.

Glass compositions and glass fibers having low dielectric constants and low dissipation factors that may be suitable for use in electronic applications and articles are disclosed. The glass fibers and compositions of the present invention may include between 48.0 to 57.0 weight percent SiO.sub.2; between 15.0 and 26.0 weight percent B.sub.2O.sub.3; between 12.0 and 18.0 weight percent Al.sub.2O.sub.3; between greater than 3.0 and 8.0 weight percent P.sub.2O.sub.5; between greater than 0.25 and 7.00 weight percent CaO; 5.0 or less weight percent MgO; and 6.0 or less weight percent TiO.sub.2. Further, the glass composition has a glass viscosity of 1000 poise at a temperature greater than 1350 degrees Celsius and a liquidus temperature greater than 1100 degrees Celsius.

An object of the present invention is to provide a less tinted LAS system crystallized glass. In the present invention, a content of each of V and Cr in the LAS system crystallized glass is 0 to 3 ppm and a content of each of Sc, La, Ce, Pr, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Ac, Th, Pa, and U is 0 to 10 ppm.