Abstract: The glasses used for making rigid disk substrates have the following composition (in % by weight based on oxides): SiO2, 40 to 50.8; Al2O3, 5 to 20; B2O3, 0 to 5; Li2O, 0 to 10; Na2O, 0 to 12, with the proviso that Li2O+Na2O, 5 to 12; K2O, 0 to 5; MgO, 0 to 20; CaO, 0 to 6, with the proviso that MgO+CaO, 4 to 20; SrO+BaO, 0 to 10; ZrO2, 0 to 5; TiO2,0 to 5; CeO2, 0 to 1; La2O3, 0 to 10; Fe2O3, 0 to 10; Nb2O5, 0 to 10; V2O5, 0 to 15, with the proviso that TiO2+ZrO2+La2O3+Fe2O3+Nb2O5+V2O5≧18.7; As2O3+Sb2O3+F. 0,1 to 1. These glasses also fulfill the following inequality formulae (1): (E/&rgr;)·+3,500 R>38.5 and 1000 R>1  (1), wherein R represents the relaxation rate of the glass and E/&rgr; represents specific elasticity modulus of the glass measured in GPA*cm3/g.

Abstract: The method for making a uniform, large-size single crystal of calcium fluoride includes placing a single precursor crystal of calcium fluoride in a tempering vessel provided with a cover; introducing calcium fluoride powder into the tempering vessel and subsequently heating the single precursor crystal, preferably in intimate contact with the calcium fluoride powder, in the tempering vessel together with the calcium fluoride powder for two or more hours at temperatures above 1150° C. to temper the precursor crystal and thus form the uniform, large-scale single crystal of calcium fluoride. The uniform large-sized single crystals of calcium fluoride can be used to make improved lens, prism, light-conducting rod, optical window or other optical component for DUV photolithography, steppers, excimer lasers, wafers, computer chips and electronic devices containing the wafers and chips.

Abstract: Magnetic disks comprising a substrate and glass materials which are used in the manufacture of hard disc substrates. The glasses can have the following compositions (in per cent by weight on an oxide basis): SiO2 10-30, Al2O3 0-5, B2O3 0-8, Li2O 0-8, Na2O 1-10, with Li2O+Na2O 5-10, K2O 0-3, MgO 5-16, CaO 0-15, with MgO+CaO>15-25, SrO+BaO 0-8, ZrO2 0-8, TiO2 7-25, La2O3 0-10, Nb2O5 5-20, V2O5 0-10, CeO2 0-1, As2O3+Sb2O3+F 0.1-1. These glasses can have high dimensional stability as a result of their high specific modulus of elasticity, to be especially suited for hard disk substrates.

Abstract: High E-moduli glasses and glass-ceramics are disclosed based on the SiO2—B2O3—RO—R2O—ZrO2—TiO2—Nb2O5—La2O3 system. The chemically pre-stressable glasses are lithium-poor or lithium-free. The glass-ceramics contain from 2 to 9 percent by weight lithium and the predominant crystalline phase is lithium titanate. These glasses and glass-ceramics particularly have a high specific E-modulus.

Abstract: The glasses used for making rigid disk substrates have the following composition (based on the % by weight of the oxides): SiO.sub.2, 40 to 60; Al.sub.2 O.sub.3, 5 to 20; B.sub.2 O.sub.3, 0 to 5; Li.sub.2 O, 0 to 10; Na.sub.2 O, 0 to 12, with the proviso that Li.sub.2 O+Na.sub.2 O 5 to 12; K.sub.2 O, 0 to 5; MgO, 0 to 20; CaO, 0 to 6, with the proviso that MgO+CaO, 4 to 20,SrO+BaO, 0 to 10; Zr.sub.2 O, 0 to 5; TiO.sub.2, 0 to 5; CeO.sub.2, 0 to 1; La.sub.2 O.sub.3, 0 to 10; Fe.sub.2 O.sub.3, 0 to 10; Nb.sub.2 O.sub.5, 0 to 10; V.sub.2 O.sub.5, 0 to 15, with the proviso that TiO.sub.2 +ZrO.sub.2 +La.sub.2 O.sub.3 +Fe.sub.2 O.sub.3 +Nb.sub.2 O.sub.3 +V.sub.2 O.sub.5 .gtoreq.8, As.sub.2 O.sub.3 +Sb.sub.2 O.sub.3 +F, 0.1 to 1; or, SiO.sub.2, 10 to 30; Al.sub.2 O.sub.3, 0 to 5; B.sub.2 O.sub.3, 0 to 8; Li.sub.2 O, 0 to 8; Na.sub.2 O, 1 to 10, with the proviso that Li.sub.2 O+Na.sub.2 O, 5 to 10; K.sub.2 O, 0 to 3; MgO, 0 to 12; CaO, 0 to 15, with the proviso that MgO+CaO,10 to 15, SrO+BaO, 0 to 8; Zr.sub.

Abstract: The chemically prestressable glass having a low bubble count and bubble size has the following composition in mol %, based on a total amount of oxides present, SiO.sub.2 from 63.0 to 67.5 mol %, Al.sub.2 O.sub.3 from 9.5 to 12.0 mol %, Na.sub.2 O from 8.5 to 15.5 mol %, K.sub.2 O from 2.5 to 4.0 mol %, MgO from 3.0 to 9.0 mol %, sum of CaO+SrO+BaO+ZnO from 0 to 2.5 mol %, TiO.sub.2 from 0.5 to 1.5 mol %, CeO.sub.2 from 0.02 to 0.5 mol %, As.sub.2 O.sub.3 from 0.02 to 0.35 mol %, SnO.sub.2 from 0. to 1.0 mol %, and F.sub.2 from 0.05 to 2.6 mol %, wherein the molar ratio ?SiO.sub.2 !/?Al.sub.2 O.sub.3 ! is 5.3 to 6.85, the molar ratio ?Na.sub.2 O!/?K.sub.2 O! is 3.0 to 5.6, the molar ratio ?Al.sub.2 O.sub.3 !/?K.sub.2 O! is 2.8 to 3.6 and the molar ratio ?Al.sub.2 O.sub.3 !/?TiO.sub.2 +CeO.sub.2 ! is 7.6 to 18.5, but, when arsenic-free, SnO.sub.2 is from 0.02 to 1.0 mol % and F.sub.2 is from greater than 0.5 to 2.6 mol %.

Abstract: The process for producing a chemically prestressed glass of very high surface quality includes subjecting an Li.sub.2 O-free starting glass from the SiO.sub.2 -Al.sub.2 O.sub.3 -M.sub.2 O-MO system which also contains TiO.sub.2, CeO.sub.2 and F.sub.2 to chemical ion exchange by immersing it in a potassium salt bath at a temperature between 350.degree. C. and 550.degree. C. and at a residence time of between 0.5 and 20 hours to form the chemically prestressed glass. In a preferred embodiment of the process, the potassium salt bath contains a potassium nitrate melt and the glass is polished after prestressing. The chemically prestressed glass is particularly useful for making hard disks.

Abstract: An aluminophosphate glass containing copper(II) oxide having a low transmission in the near infrared range with a steep absorption edge as well as a very uniform high transparency in the visible range is particularly suitable as filter glass for color video cameras or as filter glass, e.g., for goggles and color displays, said glass comprising, in % by weight on the oxide basis, 67-77 of P.sub.2 O.sub.5 ; 8-13 of Al.sub.2 O.sub.3 ; 0-5.5 of B.sub.2 O.sub.3 ; 0-2.1 of SiO.sub.2 ; 0-2.5 of Li.sub.2 O; 0-6 of Na.sub.2 O; 0-14 of K.sub.2 O; 0-2.5 of Rb.sub.2 O; 0-2.5 of Cs.sub.2 O; .SIGMA. alkali metal oxide 3-14; 2.5-4.9 of MgO; 0-2.5 of CaO; 0-2.5 of SrO; 0-2.5 of BaO; 0-2.5 of ZnO; .SIGMA. alkaline-earth metal oxides+ZnO less than 5; 2-7.5 of CuO; 0.001-0.5 of V.sub.2 O.sub.5 ; CuO+V.sub.2 O.sub.5 of 2-7.5.

Abstract: Cerium-doped radiation-shielding glasses in the system of SiO.sub.2 -PbO-alkali metal oxides, with a high absorption coefficient for high-energy X-ray and/or gamma- and, respectively, neutron radiation which are resistant to discoloration and exhibit a discharge stability of >5.times.10.sup.8 rad, consist essentially of (in % by weight)______________________________________ SiO.sub.2 35-56 Na.sub.2 O K.sub.2 O 12-21 Cs.sub.2 O PbO.sub.2 24-46 CeO.sub.2 0.5-2.5 CuO + Fe.sub.2 0-0.05; ______________________________________for absorption of neutrons, the isotope Li.sup.6 can furthermore be onctained therein, and SiO.sub.2 can be substituted by B.sub.2 O.sub.3 and/or Gd.sub.2 O.sub.3 in an amount of up to 10% by weight and Gd.sub.2 O.sub.3 is present.

Abstract: Alkali silicate glasses, colorized with Co.sup.2+ or with Co.sup.2+ and Ni.sup.2+, and having the composition:______________________________________ SiO.sub.2 52-71% by weight PbO 2.9-16.8% by weight SnO.sub.2 0.1-1.65% by weight Na.sub.2 O 6.7-16.7% by weight K.sub.2 O 0.5-9.9% by weight Na.sub.2 O + K.sub.2 O 13.3-18.3% by weight [NiO + CoO 0.1-4.4% by weight Ni.sub.2 O.sub.3 + Co.sub.2 O.sub.3 ] As.sub.2 O.sub.3 + Sb.sub.2 O.sub.3 0.05-0.5% by weight .SIGMA. RO 0-8.6% by weight B.sub.2 O.sub.3 0-8.5% by weight Al.sub.2 O.sub.3 0-0.55% by weight ZnO 0-10.5% by weight, ______________________________________in which R is Mg, Ca, Sr, Ba or a combination thereof, are disclosed. The composition of the present invention is not to include CeO.sub.2. The alkali silicate glasses of the invention are useful as optical filter glasses.

Abstract: Alkali silicate glasses, pigmented with Co.sup.2+ or with Co.sup.2+ and Ni.sup.2+, and having the composition:______________________________________ SiO.sub.2 52-71% by weight PbO 2.9-16.8% by weight SnO.sub.2 0.1-1.65% by weight Na.sub.2 O 6.7-16.7% by weight K.sub.2 O 0.5-9.9% by weight Na.sub.2 O + K.sub.2 O 13.3-18.3% by weight NiO + CoO 0.1-4.4% by weight As.sub.2 O.sub.3 + Sb.sub.2 O.sub.3 0.05-0.5% by weight .SIGMA.RO 0-8.6% by weight B.sub.2 O.sub.3 0-8.5% by weight Al.sub.2 O.sub.3 0-0.55% by weight ZnO 0-10.5% by weight, ______________________________________in which R is Mg, Ca, Sr, Ba or a combination thereof, are disclosed. The alkali silicate glasses of the invention are useful as optical filter glasses.

Abstract: Alkali silicate glasses, pigmented with Co.sup.2+ or with Co.sup.2+ and Ni.sup.2+, and having the composition:SiO.sub.2 : 52-71% by weightPbO: 2.9-16.8% by weightSnO.sub.2 : 0.1-1.65% by weightNa.sub.2 O: 6.7-16.7% by weightK.sub.2 O: 0.5-9.9% by weightNa.sub.2 O+K.sub.2 O: 13.3-18.3% by weightNiO+CoO: 0.1-4.4% by weightAs.sub.2 O.sub.3 +Sb.sub.2 O.sub.3 : 0.05-0.5% by weight.SIGMA.RO: 0-8.6% by weightB.sub.2 O.sub.3 : 0-8.5% by weightAl.sub.2 O.sub.3 : 0-0.55% by weightZnO: 0-10.5% by weight,in which R is Mg, Ca, Sr, Ba or a combination thereof, are disclosed. The alkali silicate glasses of the invention are useful as optical filter glasses.

Abstract: High PbO-content glass in the optical range of flint and heavy flint glasses from the system SiO.sub.2 --PbO--M.sub.2 O wherein M.sub.2 O=alkali metal oxides, said glass having a minimum PbO content of 30 wt. % and a minimum M.sub.2 O content of 0.5 wt. %, are provided with enhanced chemical stability without loss of the desired optical position by replacing a portion of the SiO.sub.2 and PbO such that the glass contains 1.5-6 wt. % (TiO.sub.2 +ZrO.sub.2) and the ratio of TiO.sub.2 :ZrO.sub.2 is about 0.3-2.0.

Abstract: An optical and ophthalmic glass with high refractive index, high Abbe number and low density, which is distinguished by good chemical stability, good crystallization behavior and capability of chemical hardening, comprises (in % by weight):______________________________________ SiO.sub.2 50-63 B.sub.2 O.sub.3 4-8 Al.sub.2 O.sub.3 1-2 Li.sub.2 O 4-8 Na.sub.2 O 4-8 K.sub.2 O 3-7 sum of M.sub.2 O 11-20 (M = Li, Na, K) MgO 0.5-2 CaO 2-5 sum of MO 0-3 (M = Mg, Ca) TiO.sub.2 8-12.5 ZrO.sub.2 1-3 F.sup.- 0-1 As.sub.2 O.sub.3 0.05-0.15 (optional refining agent) Sb.sub.2 O.sub.3 0.0-0.

Abstract: A phototropic glass with the optical characteristics of n.sub.d greater than to or equal to 1.59 and v.sub.d greater than or equal to 44, and with a density less than or equal to 3.0 g/cm.sup.-3 is provided having a composition comprising:______________________________________ SiO.sub.2 42-56 B.sub.2 O.sub.3 11-18 Al.sub.2 O.sub.3 0-5 sum of SiO.sub.2, B.sub.2 O.sub.3, and Al.sub.2 O.sub.3 55-75 Li.sub.2 O 3-9 Na.sub.2 O 0-7.98 K.sub.2 O 0-8.22 sum of alkaki metal oxides 7-15 MgO 3-12 CaO 0-3 SrO 0-3 BaO 0-6 ZnO 0-2 sum of alkali earth metal 3-12 oxides amd ZnO TiO.sub.2 3.06-6.74 ZrO.sub.2 2-11 Nb.sub.2 O.sub.5 2.28-8 La.sub.2 O.sub.3 0-3 Er.sub.2 O.sub.

Abstract: A colorless, cerium-and phosphorous-containing barium silicate glass, with a density of >3.3 g/cm.sup.2, a radiation length <43.5 mm, with strong fluorescence at 415-430 nm and with good scintillation properties, consisting essentially of (in percent by weight):______________________________________ SiO.sub.2 20-60 B.sub.2 O.sub.3 0-18 21-60 P.sub.2 O.sub.5 1-10 Li.sub.2 O 0-10 Na.sub.2 O 0-10 K.sub.2 O 0-15 MgO 0-10 SrO 0-12 BaO 30-60 30-60 La.sub.2 O.sub.3 0-10 Ce.sub.2 O.sub.3 0.5-8 Other oxides 0-20 Al.sub.2 O.sub.

Abstract: An optical and ophthalmic glass with high refractive index, high Abbe number and low density, which is distinguished by good chemical stability, good crystallization behavior and capability for chemical hardening, comprises (in % by weight):SiO.sub.2 --47 to 75B.sub.2 O.sub.3 --1 to 20Al.sub.2 O.sub.3 --0 to 10P.sub.2 O.sub.5 --0 to 5Li.sub.2 O--0 to 15Na.sub.2 O--0 to 10K.sub.2 O--0 to 10CaO--0 to 20MgO--0 to 15SrO--0 to 4BaO--0 to 4ZnO--0 to 5TiO.sub.2 --1 to 15ZrO.sub.2 --0 to 8Nb.sub.2 O.sub.5 --0 to 5 andF----0 to 5.

Abstract: These objects have been attained by providing highly absorbent lead containing alkali metal silicate glasses for cathode ray tube image screens, having a linear absorption coefficient .mu. of >30 cm.sup.-1 (0.6 .ANG.) and with a high resistance to discoloration by X-ray and electron radiation, comprises, in weight percent:______________________________________ SiO.sub.2 20-65% P.sub.2 O.sub.5 + B.sub.2 O.sub.3 + Al.sub.2 O.sub.3 0-30% Li.sub.2 O 0-5% Na.sub.2 O 0-10% K.sub.2 O 0-15% MgO + CaO + ZnO 0-15% SrO 0-20% BaO 0-40% PbO 5-60% ZrO.sub.2 0-10% CeO.sub.2 0.1-5% Other Components 0-20%.

Abstract: A spectacle glass which is colorless in the visible spectrum range, not transmissive in the ultraviolet spectrum range below 350 nm, has a refractive index n.sub.d higher than 1.56 and an Abbe number of more than 45, and which has an extremely low density, has the following composition (in % by weight):______________________________________ 12-40 P.sub.2 O.sub.5 13-34 Al.sub.2 O.sub.3 8-30 SiO.sub.2 0-16 B.sub.2 O.sub.3 4-12 TiO.sub.2 0-4 ZrO.sub.2 2-18 CaO 0-4 MgO 0-15 Na.sub.2 O 0-11 K.sub.2 O 0-6 Li.sub.2 O 0-12 Nb.sub.2 O.sub.5 0-8 ZnO.

Abstract: A new phototropic glass in which the phototropic properties arise from precipitations of silver halide and which in the unirradiated condition is slightly tinted or completely colorless while showing a brown color in the light-exposed condition, comprises, in known phototropic glass compositions, an additional content of at least 0.001 wt % of TeO.sub.2 and/or Yb.sub.2 O.sub.3.