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.

A colored glass article may include 50-80 mol % SiO.sub.2; 7-20 mol % Al.sub.2O.sub.3; 1-35 mol % R.sub.2O, wherein R.sub.2O comprises at least one of Li.sub.2O, Na.sub.2O, and K.sub.2O; 1×10.sup.−6-10 mol % of a colorant, wherein the colorant comprises at least one of Cr.sub.2O.sub.3, Au, Ag, CuO, NiO, Co.sub.3O.sub.4, TiO.sub.2, CeO.sub.2; and 12-24 mol % of Al.sub.2O.sub.3+MgO+CaO+ZnO. The colored glass article may have a transmittance color coordinate in the CIELAB color space with an L* value of 55 to 96.5. The colored glass article may have a compressive stress profile with a depth of compression ≥0.15t, a thickness t from 0.4 mm-5 mm, a compressive stress ≥200 MPa, and a central tension ≥60 MPa. The colored glass article may have a dielectric constant from 5.6 to 6.4 over the frequency range from 10 GHz to 60 GHz.

One aspect relates to a process for the preparation of a quartz glass body including, providing a silicon dioxide granulate obtainable from a silicon dioxide powder, wherein the silicon dioxide granulate has a larger particle size than the silicon dioxide powder, making a 5 glass melt out of silicon dioxide granulate and making a quartz glass body out of at least part of the glass melt. The melting crucible has at least one inlet and at least one outlet. A least part of the glass melt is removed via the melting crucible outlet. One aspect further relates to a quartz glass body which is obtainable by this process. One aspect further relates to a light guide, an illuminant and a formed body, which are each obtainable by further processing 10 of the quartz glass body.

A colored glass article may include 50-80 mol % SiO.sub.2; 7-20 mol % Al.sub.2O.sub.3; 1-35 mol % R.sub.2O, wherein R.sub.2O comprises at least one of Li.sub.2O, Na.sub.2O, and K.sub.2O; 1×10.sup.−6-10 mol % of a colorant, wherein the colorant comprises at least one of Cr.sub.2O.sub.3, Au, Ag, CuO, NiO, Co.sub.3O.sub.4, TiO.sub.2, CeO.sub.2; and 12-24 mol % of Al.sub.2O.sub.3+MgO+CaO+ZnO. The colored glass article may have a transmittance color coordinate in the CIELAB color space with an L* value of 55 to 96.5. The colored glass article may have a compressive stress profile with a depth of compression ≥0.15t, a thickness t from 0.4 mm-5 mm, a compressive stress ≥200 MPa, and a central tension ≥60 MPa. The colored glass article may have a dielectric constant from 5.6 to 6.4 over the frequency range from 10 GHz to 60 GHz.

To provide an optical glass having a high refractive index and a relatively low specific gravity, and an optical element.

An optical glass which is a SiO.sub.2—TiO.sub.2—Nb.sub.2O.sub.5-based glass, and in which the content of SiO.sub.2 is 10% by mass or greater, the total content of Na.sub.2O, K.sub.2O, and Cs.sub.2O(Na.sub.2O+K.sub.2O+Cs.sub.2O) is 11.0% by mass or less, and the specific gravity and the refractive index nd thereof satisfy formula (1).

nd≥0.2×specific gravity+1.18  (1):

A tubular member for an exhaust gas treatment device according to at least one embodiment of the present invention includes: a tubular main body made of a metal; and an insulating layer formed at least on an inner peripheral surface of the tubular main body. The insulating layer contains glass containing a crystalline substance, and the glass contains silicon, boron, and magnesium.

A chemically toughenable or toughened sheet-like glass article is provided. The article has a glass with a composition comprising Al.sub.2O.sub.3, SiO.sub.2, Li.sub.2O, and Na.sub.2O, wherein (Al.sub.2O.sub.3)−(Li.sub.2O+Na.sub.2O), in mol %, is less than 0; a thickness between 0.3 mm and 4 mm; a light transmittance of at least 0.001% to at most 60% at 450 nm, of at least 0.001% to at most 30% at 540 nm, and of at least 0.001% to at most 30% at 630 nm; and an IR transmittance of at least 10% to not more than 99% at any wavelength in a wavelength range from 900 nm to 1100 nm. The light and IR transmittances are determined for a thickness of the article of 1 mm.

Glass-based articles having sections of different thicknesses where a maximum central tension in a thinner section is less than that of a thicker section. The articles comprise an alkali metal oxide having a independent nonzero concentrations that vary along at least a portion of the thickness of each section. Consumer electronic products may comprise the glass-based articles having sections of different thicknesses.

A glass powder composite includes a first glass powder, and a second glass powder having a different solubility from that of the first glass powder depending on pH, wherein both the first glass powder and the second glass powder have ion sustained-release properties.

A copper dopant delivery powder comprising a fused silica powder and a Cu.sub.2S powder. A method of making the copper dopant delivery powder. A method of making a copper-doped glass comprising placing a target glass in a container, packing a composite SiO.CuS dopant powder around the target glass and heating the container and SiO.CuS dopant powder to a temperature of between 800° C. and 1150° C. A copper-doped glass comprising a glass comprising copper-doping wherein the copper-doped glass was formed by covering the glass with a fused silica powder and a Cu.sub.2S powder, wherein the fused silica powder and the Cu.sub.2S powder are mixed in varying ratios of Cu.sub.2S to silica represented by the formula (SiO.sub.2).sub.(1-x)(Cu.sub.2S).sub.x and heating to a temperature of between 800° C. and 1150° C.