Abstract: This invention is directed to the production of glasses especially suitable for use as ophthalmic lenses which exhibit indices of refraction between about 1.699-1.703, Abbe numbers equal to or greater than 41.0, densities less than 3.25 g/cm.sup.3, and good resistance to attack by acids. The glasses are essentially free of Al.sub.2 O.sub.3 and consist essentially, in weight percent on the oxide basis, of:______________________________________ SiO.sub.2 33-37 CaO 8-9.5 B.sub.2 O.sub.3 7.5-13 SrO 2-4 SiO.sub.2 + B.sub.2 O.sub.3 44-48 La.sub.2 O.sub.3 12.3-14.5 Li.sub.2 O 5-8 ZrO.sub.2 4-6 Na.sub.2 O 0-2.5 Nb.sub.2 O.sub.5 8-10.5 K.sub.2 O 0-2 TiO.sub.2 5-7 Li.sub.2 O + Na.sub.2 O + K.sub.2 O 5-8 As.sub.2 O.sub.3 0-0.8.

Abstract: This invention is related to glasses particularly useful in the fabrication of multifocal lenses for ophthalmic applications. The inventive glasses exhibit a refractive index between 1.599-1.602, an Abbe number between 40.5-41.5, a density between 2.64-2.66 g/cm.sup.3, a transmission of visible radiation at 400 nm through a thickness of 10 mm greater than 83%, a softening point between 670.degree.-680.degree. C., a birefringence upon sealing, measured as described, between -150 and +150 nm/cm, and consist essentially, expressed in terms of weight percent on the oxide basis, of:______________________________________ SiO.sub.2 52-57 K.sub.2 O 11.0-16.0 B.sub.2 O.sub.3 2.5-7.0 CaO 2-3.5 Al.sub.2 O.sub.3 0-1 ZrO.sub.2 1-1.5 Li.sub.2 O 0.3-0.8 TiO.sub.2 15.0-16.2 Na.sub.2 O 5.4-8.2 As.sub.2 O.sub.3 0.1-0.

Abstract: This invention is concerned with a glass for optical and/or ophthalmic applications having an index of refraction between about 1.78-1.82, an Abbe number greater or equal to 31, and a density less than about 3.80 g/cm.sup.3 consisting essentially, expressed in terms of weight percent on the oxide basis, of:______________________________________ SiO.sub.2 15-30 CaO 15-28 B.sub.2 O.sub.3 2-17 SrO 0-11 SiO.sub.2 + B.sub.2 O.sub.3 24-36 BaO 0-11 Al.sub.2 O.sub.3 0-6.5 MgO + CaO + 16-33 SrO + BaO Li.sub.2 O 0-5 ZnO 0-11 Na.sub.2 O 0-5 La.sub.2 O.sub.3 16-30 K.sub.2 O 0-5 ZrO.sub.2 0-10 Li.sub.2 O + Na.sub.2 O + K.sub.2 O 0-6 Nb.sub.2 O.sub.5 5-26 MgO 0-6 TiO.sub.2 0-14.

Abstract: The invention relates to the glass industry. It concerns glasses of low lead content characterized in being prepared from glass forming batches consisting essentially, in weight percent on the oxide basis of:______________________________________ SiO.sub.2 66-70 BaO 5-9.5 B.sub.2 O.sub.3 0-3 PbO 1.5-5 Al.sub.2 O.sub.3 2-4.5 MgO + CaO 0-3.5 Li.sub.2 O 0.5-1.6 As.sub.2 O.sub.3 + Sb.sub.2 O.sub.3 0-1 Na.sub.2 O 7-9.5 BaO + MgO + CaO 8-11 K.sub.2 O 5-8.5 Li.sub.2 O + Na.sub.2 O + K.sub.2 O 14.5-17 Na.sub.2 O:K.sub.2 O <1.7 ______________________________________A specific application of the invention is the fabrication of electrical devices such as light bulbs.

Abstract: This invention is concerned with the production of glasses suitable for ophthalmic applications having refractive indices of 1.523.+-.0.004, Abbe number between 51-59, densities less than 2.43 g/cm.sup.3, transmissions at 400 nm in 2 mm thickness greater than 89%, and a UV cutoff between 310-335 nm, said glasses consisting essentially, in weight percent on the oxide basis, of:______________________________________ SiO.sub.2 49-71 Li.sub.2 O + Na.sub.2 O + K.sub.2 O 8-20 B.sub.2 O.sub.3 5-26 TiO.sub.2 1.8-6 Al.sub.2 O.sub.3 0-14 ZrO.sub.2 0-5.5 Li.sub.2 O 0-4 As.sub.2 O.sub.3 and/or Sb.sub.2 O.sub.3 0-0.7 Na.sub.2 O 0-16 Cl and/or Br 0-1 K.sub.

Abstract: This invention relates to glasses especially suitable for optical and ophthalmic applications which exhibit densities less than about 2.65 g/cm.sup.3, refractive indices between about 1.595-1.607, and Abbe numbers between about 40-47, and which consist essentially, in weight percent on the oxide basis, of______________________________________ SiO.sub.2 45-55 MgO and/or BaO and/or B.sub.2 O.sub.3 5-13 SrO and/or La.sub.2 O.sub.3 0-6 Al.sub.2 O.sub.3 0-5 CaO 0-12 Li.sub.2 O 1-7.5 ZnO 0-8 Na.sub.2 O 1-9 ZrO.sub.2 0-7 K.sub.2 O >10-24 TiO.sub.2 9.5-17.5 As.sub.2 O.sub.3 and/or Sb.sub.2 O.sub.3 0-1 and 13.5 < TiO.sub.2 + ZrO.sub.2 + La.sub.2 O.sub.3 + MgO <23.

Abstract: This invention is concerned with the preparation of moldable optical glasses having refractive indices of about 1.65-1.735, dispersions of about 38-58, transition temperatures lower than about 500.degree. C., softening points lower than about 600.degree. C., and satisfactory chemical durability consisting essentially, expressed in terms of parts by weight as calculated from the batch, of______________________________________ B.sub.2 O.sub.3 22-38 BaO 3-33 La.sub.2 O.sub.3 5-33 PbO 0-36 ZnO 0-14 CdO 0-12 SrO 0-10 BaO + La.sub.2 O.sub.3 + PbO + ZnO + CdO + SrO 55-68 Li.sub.2 O 0-4 Na.sub.2 O 0-4 Li.sub.2 O + Na.sub.2 O 1.5-4 F 1-8.

Abstract: This invention relates to the production of glasses especially suitable for ophthalmic lenses, the glasses exhibiting refractive indices between about 1.695-1.705, dispersive indices between about 40.5-43.2, densities below about 3.2 g/cm.sup.3, weight losses as measured in the AO test of less than 0.15 mg/cm.sup.2, transmittances at 400 nm in 10 mm thickness of at least 75%, and consisting essentially, in weight percent of______________________________________ CaO 16-21.5 La.sub.2 O.sub.3 6-15 TiO.sub.2 3.5-<9 Al.sub.2 O.sub.3 5.5-12 Nb.sub.2 O.sub.5 3-11 ZrO.sub.2 2-10 B.sub.2 O.sub.3 20.5-25 SiO.sub.

Abstract: This invention is directed to the production of glasses having a density of less than 3.26 g/cm.sup.3, a .beta..sub.OH value less than 0.030 mm.sup.-1, and, in a thickness of 2 mm, a transmission of at least about 80% at a wavelength of 4.0 microns and at least about 50% at a wavelength of 5 microns, which have base compositions within the alkali metal oxide-CaO-Al.sub.2 O.sub.3 -GeO.sub.2 -F and/or Cl field consisting essentially, expressed in terms of weight percent on the oxide basis, of______________________________________ GeO.sub.2 36-55 Al.sub.2 O.sub.3 18-31 CaO 10-25 Li.sub.2 O 0-5 K.sub.2 O and/or Na.sub.2 O and/or Li.sub.2 O 7-20 Al.sub.2 O.sub.3 + 1.5 (K.sub.2 O and/or Na.sub.2 O and/or Li.sub.2 .gtoreq.40 F and/or Cl 0.1-4.

Abstract: The present invention is drawn to glasses suitable for the fabrication of segments or buttons for multifocal ophthalmic lenses. The inventive glasses have refractive indices ranging between about 1.745-1.771, an Abbe number greater than 29 for a refractive index of 1.771 and greater than 31 for a refractive index of 1.745, a softening point between about 640.degree.-700.degree. C., a coefficient of thermal expansion (25.degree.-300.degree. C.) between about 90-98.times.10.sup.-7 /.degree.C., and satisfactory chemical durability. The glasses consist essentially, expressed in terms of weight percent on the oxide basis, of______________________________________ SiO.sub.2 28-32.5 Na.sub.2 O 2-9 K.sub.2 O 0-4 Li.sub.2 O 0-1 K.sub.2 O + Na.sub.2 O + Li.sub.2 O 4-10.5 BaO 0-22 La.sub.2 O.sub.3 0-20 BaO + La.sub.2 O.sub.3 14-22 PbO 28.5-34 ZnO 0-4 TiO.sub.2 0-9 ZrO.sub.2 2-6.5 Nb.sub.2 O.sub.5 0-10 TiO.sub.2 + Nb.sub.2 O.sub.5 4.5-12 ZrO.sub.2 + TiO.sub.2 + Nb.sub.2 O.sub.

Abstract: This invention is concerned with sealing glasses exhibiting a coefficient of absorption of infra-red radiation within the range of 0.7-4 microns of at least 98%, an average coefficient of thermal expansion over the range of 20.degree.-300.degree. C. between 88-92.5.times.10.sup.-7 /.degree.C., and a volatilization of less than about 200 ppm at the sealing temperature, said glass being essentially free from K.sub.2 O and B.sub.2 O.sub.3 and consisting essentially, in weight percent on the oxide basis as calculated from the batch, of______________________________________ SiO.sub.2 67-73 Al.sub.2 O.sub.3 3.5-6.0 Li.sub.2 O 1.0-3.0 Na.sub.2 O 10-16 BaO 3.0-5.5 Fe.sub.2 O.sub.3 2.0-4.0 F 0.1-0.4 TiO.sub.2 0-3 ZrO.sub.2 0-3 ZnO 0-2 TiO.sub.2 + ZrO.sub.2 + ZnO 0-4 ______________________________________the sum of those components constituting at least 98% by weight of the glasses. The glasses are especially suitable as envelopes for reed switches.

Abstract: The instant invention relates to glasses suitable for optical and ophthalmic applications which can be melted and formed utilizing continuous commercial processes. The glasses exhibit indices of refraction between about 1.675-1.720, densities between about 3.1-3.4 g/cm.sup.3, Abbe numbers between about 33-36.5, viscosities at the liquidus temperature of at least about 220 poises, and very high chemical durability as evidenced by a loss of weight of less than 0.01 mg/cm.sup.2 in the American Optical test. The glasses consist essentially, in weight percent on the oxide basis, of 40-46% SiO.sub.2, 0-3% Al.sub.2 O.sub.3, 40-46% SiO.sub.2 +Al.sub.2 O.sub.3, 13-17% TiO.sub.2, 4-11% ZrO.sub.2, 0-2% MgO, 3-7% CaO, 4-8% CaO+MgO, 8-16% BaO, 0-4% SrO, 15-25% CaO+BaO+SrO, 2-10% Nb.sub.2 O.sub.5, 0-3% Li.sub.2 O, 2-7% Na.sub.2 O, 3-8% K.sub.2 O, 5-12% Li.sub.2 O+Na.sub.2 O+K.sub.2 O.

Abstract: Glasses are disclosed that have a high refractive index on the order of 1.7 or greater, a low density on the order of 3 gm./cm..sup.3, good chemical durability and a dispersive index on the order of 40 or more. These glasses belong to a CaO--La.sub.2 O.sub.3 --TiO.sub.2 --B.sub.2 O.sub.3 --SiO.sub.2 family and are particularly useful in strong correction ophthalmic lenses and space optics.