A redrawing method for the production of thin glasses is provided that allows redraw of high refractive index optical glasses. The includes the steps of providing a vitreous preform with a mean width B, a mean thickness D, and a refractive index n.sub.D of at least 1.68 in a redrawing device, heating at least a part of the preform, redrawing of the preform to a thin glass with a mean width b and a mean thickness d. The heated part of the preform exhibits, for the duration of at most 30 minutes, a temperature above a lower limit of devitrification of the glass. The glass of the preform exhibits a dependence of the viscosity on the temperature, which is characterized by a mean decrease of the viscosity with increasing temperature in an viscosity range of 10.sup.8 to 10.sup.5 dPas of at least 3*10.sup.5 dPas/K.

A redrawing method for the production of thin glasses is provided that allows redraw of high refractive index optical glasses. The includes the steps of providing a vitreous preform with a mean width B, a mean thickness D, and a refractive index n.sub.D of at least 1.68 in a redrawing device, heating at least a part of the preform, redrawing of the preform to a thin glass with a mean width b and a mean thickness d. The heated part of the preform exhibits, for the duration of at most 30 minutes, a temperature above a lower limit of devitrification of the glass. The glass of the preform exhibits a dependence of the viscosity on the temperature, which is characterized by a mean decrease of the viscosity with increasing temperature in an viscosity range of 10.sup.8 to 10.sup.5 dPas of at least 3*10.sup.5 dPas/K.

Disclosed is a sealing glass composition substantially not containing B.sub.2O.sub.3 or Al.sub.2O.sub.3, which is a high-strength, high-expansive crystallizing glass composition that can be used at high temperatures of not less than 950° C. The composition substantially not containing boron oxide, alkali metal oxides or aluminum oxide, but containing, in mol %, SiO.sub.2: 40-55, BaO: 18-35, TiO.sub.2+ZrO.sub.2: 0.1-10, ZnO: 0-15, CaO: 0-20, MgO: 0-9, SrO: 0-5, and La.sub.2O.sub.3: 0-2, wherein the total content of RO (R: Mg, Ca, Sr, Ba and Zn) is at least 44 mol %, and wherein the glass composition, when fired in the form of glass powder at a temperature of 850-1050° C, turns into a crystallized glass that exhibits a thermal expansion coefficient of 90-150×10.sup.−7/° C. in the range of 50-850° C.

Disclosed is a sealing glass composition substantially not containing B.sub.2O.sub.3 or Al.sub.2O.sub.3, which is a high-strength, high-expansive crystallizing glass composition that can be used at high temperatures of not less than 950° C. The composition substantially not containing boron oxide, alkali metal oxides or aluminum oxide, but containing, in mol %, SiO.sub.2: 40-55, BaO: 18-35, TiO.sub.2+ZrO.sub.2: 0.1-10, ZnO: 0-15, CaO: 0-20, MgO: 0-9, SrO: 0-5, and La.sub.2O.sub.3: 0-2, wherein the total content of RO (R: Mg, Ca, Sr, Ba and Zn) is at least 44 mol %, and wherein the glass composition, when fired in the form of glass powder at a temperature of 850-1050° C, turns into a crystallized glass that exhibits a thermal expansion coefficient of 90-150×10.sup.−7/° C. in the range of 50-850° C.

The present invention relates to inorganic fibres having a composition comprising: 65.7 to 70.8 wt % SiO.sub.2; 27.0 to 34.2 wt % CaO; 0.10 to 2.0 wt % MgO; and optional other components providing the balance up to 100 wt %,
wherein the sum of SiO.sub.2 and CaO is greater than or equal to 97.8 wt %; and the other components, when present, comprise no more than 0.80 wt % Al.sub.2O.sub.3; and wherein the amount of MgO and other components are configured to inhibit the formation of surface crystallite grains upon heat treatment at 1100° C. for 24 hours, wherein said surface crystallite grains comprise an average crystallite size in a range of from 0.0 to 0.90 μm.

To provide a glass plate which is hardly broken and which has a high infrared transmittance.

A glass plate, which has a thickness of from 1 to 8 mm, has an infrared transmittance T3000 at a wavelength of 3,000 nm of at least 4%, an average thermal expansion coefficient a at from 50 to 350° C. of from 15 to 35×10.sup.−7/° C., and a glass composition comprising, as represented by mol% based on oxides, from 50 to 85% of SiO.sub.2, from 0.1 to 25% of Al.sub.2O.sub.3, from 0.1 to 20% of B.sub.2O.sub.3, from 0 to 20% in total of at least one member selected from MgO, CaO, SrO, BaO and ZnO, and from 0 to 20% in total of at least one member selected from Li.sub.2O, Na.sub.2O and K.sub.2O.

To provide a glass plate which is hardly broken and which has a high infrared transmittance.

A glass plate, which has a thickness of from 1 to 8 mm, has an infrared transmittance T3000 at a wavelength of 3,000 nm of at least 4%, an average thermal expansion coefficient a at from 50 to 350° C. of from 15 to 35×10.sup.−7/° C., and a glass composition comprising, as represented by mol% based on oxides, from 50 to 85% of SiO.sub.2, from 0.1 to 25% of Al.sub.2O.sub.3, from 0.1 to 20% of B.sub.2O.sub.3, from 0 to 20% in total of at least one member selected from MgO, CaO, SrO, BaO and ZnO, and from 0 to 20% in total of at least one member selected from Li.sub.2O, Na.sub.2O and K.sub.2O.

Compounds, compositions, articles, devices, and methods for the manufacture of light guide plates and back light units including such light guide plates made from glass. In some embodiments, light guide plates (LGPs) are provided that have similar or superior optical properties to light guide plates made from PMMA and that have exceptional mechanical properties such as rigidity, CTE and dimensional stability in high moisture conditions as compared to PMMA light guide plates.

Compounds, compositions, articles, devices, and methods for the manufacture of light guide plates and back light units including such light guide plates made from glass. In some embodiments, light guide plates (LGPs) are provided that have similar or superior optical properties to light guide plates made from PMMA and that have exceptional mechanical properties such as rigidity, CTE and dimensional stability in high moisture conditions as compared to PMMA light guide plates.

A method for winding up a glass ribbon is provided, in which, prior to winding up the glass ribbon, the two surfaces of the glass ribbon are each initially treated with a water-containing medium and subsequently dried so as to produce a defined content of water molecules on the two surfaces, by achieving a saturation of the surfaces of the glass ribbon with water, without bringing about an excess of water molecules. A glass roll is produced in which the electrostatic charge of the glass surface is reduced and, as a result, any undesired excess adherence of the glass surface to an interleaf material is prevented and, in this way, glass breakage, in particular during winding up and/or unwinding of the glass roll, can be markedly reduced.