Abstract: A core glass and a fiber-optic light guide made from it and a cladding glass are described. The core glass is in the alkali-zinc-silicate system and contains, in Mol % on an oxide basis: 54.5-65, SiO2; 18.5-30, ZnO; 8-20, ? alkali metal oxides; 0.5-3, La2O3; 2-5, ZrO2; 0.02-5, HfO2; 2.02-5, ? ZrO2+HfO2; 0.4-6, BaO; 0-6, SrO; 0-2, MgO; 0-2, CaO; 0.4-6, ? alkaline earth metal oxides; 0.5-3, Li2O, but no more Li2O than 25% of the ? alkali metal oxides; >58.5, ? SiO2+ZrO2+HfO2. A molar ratio of Na2O/K2O is from 1/1.1 to 1/0.3. A molar ratio of ZnO to BaO is greater than 3.5.

Abstract: A core glass and a fiber-optic light guide made from it are described. The core glass is in the alkali-zinc-silicate system and contains, in Mol % on an oxide basis: 54.5-65, SiO2; 18.5-30, ZnO; 8-20, ? alkali oxides; 0.5-3, La2O3; 2-5, ZrO2; 0.02-5, HfO2; 2.02-5, ?ZrO2+HfO2; 0.4-6, BaO; 0-6, SrO; 0-2, MgO; 0-2, CaO; 0.4-6, ? alkaline earth oxides; 0.5-3, Li2O, but no more Li2O than 25% of the ? alkali oxides; >58.5, ? SiO2+ZrO2+HfO2. A molar ratio of Na2O/K2O is from 1/1.1 to 1/0.3. A molar ratio of ZnO to BaO is greater than 3.5.

Abstract: The invention concerns an optical colored glass with a composition (in percent by weight based on oxide) of SiO2 30–75; K2O 5–35; B2O3>4–17; ZnO 5–37; F 0.01–10; CdO 0.1–1, S+Se+Te 0.1–1.5 as well as the use of this glass as a long-pass cutoff filter.

Abstract: The invention concerns an optical colored glass with a composition (in percent by weight based on oxide) of SiO2 30-75; K2O 5-35; B2O3>4-17; ZnO 5-37; F 0.01-10; CdO 0.1-1, S+Se+Te 0.1-1.5 as well as the use of this glass as a long-pass cutoff filter.

Abstract: The invention concerns an optical colored glass with a composition (in percent by weight based on oxide) of

Abstract: The lead-free bismuth-containing silicate glasses, which are particularly suitable for use as funnel glass or neck glass for cathode ray tubes and as soldering glass, have the following respective compositions (in % by weight, based on oxide): SiO2 40-60; Bi2O3, 10-30; ZrO2, 0-3; Al2O3, 0.5-5; MgO, 0-6; CaO, 0.5-5; SrO, 1-15; BaO, 0-15; sum of the alkaline earth metal oxides, 2-20; ZnO, 0-2; Li2O, 0-10; Na2O, 1-10; K2O, 2-10; Cs2O, 0-3, sum of the alkali metal oxides, 5-20; CeO2, 0-8; WO3, 0.5-5; MoO3, 0-5 and Sb2O3, 0-0.6; and SiO2 30-50; Bi2O3, 20-40; ZrO2, 0-3; Al2O3, 0.5-5; MgO, 0-4; CaO, 0.5-4; SrO, 1-15; BaO, 0-15; sum of the alkaline earth metal oxides, 2-20; ZnO, 0-2; Li2O, 0-5; Na2O, 1-12; K2O, 2-15; Cs2O, 0-3, sum of the alkali metal oxides, 5-20; CeO2, 0-8; WO3, 0.5-5; MoO3, 0-5 and Sb2O3, 0-0.6.

Abstract: The invention relates to lead-free optical glasses having a refractive index nd of from 1.52 to 1.58, an Abbe number vd of from 50 to 57 and a negative partial dispersion &Dgr;Pg,F of <−0.0090, having a composition (in % by weight, based on oxide) of SiO2>15-25; B2O3 45-55; Al2O3 8-13; CaO 2-8; ZnO 0-5; with CaO+ZnO 2-10; Li2O 0-4; Na2O 0-4; K2O 0-4; with Li2O+Na2O+K2O 3-8; La2O3 0-14; Nb2O5 0-4.8; Ta2O5>10-17; with Ta2O5+Nb2O5>10-17; SnO2 0-2; ZrO2 0-7; with Ta2O5+ZrO2>10-<18.

Abstract: The invention can relate to essentially lead-free optical glasses having a refractive index nd of from about 1.65 to about 1.87 and an Abbe number &ngr;d of from about 27 to about 43 and a composition (in % by weight, based on oxide) of SiO2 about 10-about 25, B2O3>about 10-about 25, Na2O about 2.5-about 10, K2O 0-about 3, CaO about 0.5-about 5, BaO about 15-about 30, ZnO about 5-about 15, TiO2 about 6-about 15, ZrO2 about 0.5-about 8, Y2O3 about 0.1-about 2, La2O3 about 0.5-about 8, Nb2O5 about 6-about 12, with La2O3+Nb2O5≦about 17,Ta2O5 0-about 1, and Gd2O3 0-about 1.

Abstract: The lead-free bismuth-containing silicate glasses, which are particularly suitable for use as funnel glass or neck glass for cathode ray tubes and as soldering glass, have the following respective compositions (in % by weight, based on oxide): SiO2 40-60; Bi2O3, 10-30; ZrO2, 0-3; Al2O3, 0.5-5; MgO, 0-6; CaO, 0.5-5; SrO, 1-15; BaO, 0-15; sum of the alkaline earth metal oxides, 2-20; ZnO, 0-2; Li2O, 0-10; Na2O, 1-10; K2O, 2-10; Cs2O, 0-3, sum of the alkali metal oxides, 5-20; CeO2, 0-8; WO3, 0.5-5; MoO3, 0-5 and Sb2O3, 0-0.6; and SiO2 30-50; Bi2O3, 20-40; ZrO2, 0-3; Al2O3, 0.5-5; MgO, 0-4; CaO, 0.5-4; SrO, 1-15; BaO, 0-15; sum of the alkaline earth metal oxides, 2-20; ZnO, 0-2; Li2O, 0-5; Na2O, 1-12; K2O, 2-15; Cs2O, 0-3, sum of the alkali metal oxides, 5-20; CeO2, 0-8; WO3, 0.5-5; MoO3, 0-5 and Sb2O3, 0-0.6.

Abstract: The invention relates to a copper(II) oxide-containing aluminophosphate glass having good chemical resistance, very good devitrification stability, high transmission at wavelengths in the range from 350 to 550 nm and a refractive index n.sub.d of from 1.52 to 1.54. The glass has the following composition (in % by weight, based on oxide): Al.sub.2 O.sub.3 4-9; P.sub.2 O.sub.5 67-75; BaO 0.5-6; CaO 0.1-1; MgO 0-4; SrO 0-1; ZnO 0.2-1; .SIGMA.BaO+CaO+MgO+SrO+ZnO 3.5-7; Na.sub.2 O 1.5-5; K.sub.2 O 2.5-3.5; Li.sub.2 O 0.5-5; .SIGMA.Na.sub.2 O+K.sub.2 O+Li.sub.2 O 5-13; SiO.sub.2 0-1; B.sub.2 O.sub.3 1-2.5; AS.sub.2 O.sub.3 0.1-0.5; Cl.sup.- 0-0.3; F.sup.- O-1.3; CeO.sub.2 0.2-0.4; CuO 1-6; with K.sub.G =.SIGMA.Al.sub.2 O.sub.3 +SiO.sub.2 +CeO.sub.2 /.SIGMA.P.sub.2 O.sub.5 +B.sub.2 O.sub.3 0.06-0.125.

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: Infrared-transparent bi- or multicomponent chalcogenide glasses based on germanium and selenium are improved by doping with 0.05 to 1.0 atom % of at least one of the alkaline earth metals calcium or strontium and/or one of their compounds. Optical fibers and optical elements can be made from these glasses.