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 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: The present invention is directed to fluorophosphate glasses containing about 3-21.5% Nb.sub.2 O.sub.5 and exhibiting softening points below 500.degree. C. The inventive glasses contemplate two general composition areas in weight percent:______________________________________ P.sub.2 O.sub.5 35-46 P.sub.2 O.sub.5 20-35 Al.sub.2 O.sub.3 3.5-6.5 Li.sub.2 O 0.5-5 Li.sub.2 O 0.8-3.0 Na.sub.2 O 0-10 Na.sub.2 O 3-10 Li.sub.2 O + Na.sub.2 O 0.5-10 Li.sub.2 O + Na.sub.2 O 5-10.5 PbO 0-40 BaO 18-44 Sb.sub.2 O.sub.3 0-25 CaO 0-12 PbO + Sb.sub.2 O.sub.3 20-50 SrO 0-15 BaO 0-20 MgO 0-7 Al.sub.2 O.sub.3 0-5 BaO + CaO + SrO + MgO 28-47 Nb.sub.2 O.sub.5 13-21.5 CaO + SrO + MgO <15 F 1-12 Nb.sub.2 O.sub.5 3-8.5 F 4.

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 concerned with the production of photochromic glass compositions consisting essentially, expressed in terms of weight percent on the oxide basis, as calculated from the batch, of______________________________________ SiO.sub.2 52-59 B.sub.2 O.sub.3 18-23 Al.sub.2 O.sub.3 6-8 Li.sub.2 O 1-2.5 Na.sub.2 O 1-3 K.sub.2 O 8-13 ZrO.sub.2 2-6 TiO.sub.2 0-3 ______________________________________and containing, as analyzed in weight percent, of ______________________________________ Ag 0.17-0.22 CuO 0.012-0.019 Cl 0.29-0.35 Br 0.06-0.12 PbO 0.1-0.15 ______________________________________exhibiting, in 0.4 mm cross section, a clear luminous transmittance in excess of 90%, a darkened luminous transmittance below about 45% at a temperature of 25.degree. C., a darkened luminous transmittance below about 57% at a temperature of 40.degree. C., and a half fading time at both temperatures of about five minutes.

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: The instant invention is related to the manufacture of photochromic glasses having base compositions within a very narrow interval of the alkali metal boroaluminosilicate system wherein silver chloride and/or silver bromide crystals impart photochromic properties. The glasses are notable for their rapid fading characteristics and relatively low temperature dependence of darkening. The compositions are especially suitable for a production process which contemplates simultaneously shaping articles from glass sheet and developing photochromic properties therein.

Abstract: The instant invention is related to the manufacture of photochromic glasses having base compositions within a very narrow interval of the alkali metal boroaluminosilicate system wherein silver chloride and/or silver bromide crystals impart photochromic properties. The glasses are notable for their rapid fading characteristics and relatively low temperature dependence of darkening. The compositions are especially suitable for a production process which contemplates simultaneously shaping articles from glass sheet and developing photochromic properties therein.