Abstract: This invention is directed to the preparation of glasses in the PbO--Ga.sub.2 O.sub.3 field exhibiting good infrared transmitting characteristics out to wavelengths of 8 microns. The binary glasses consist essentially, by weight, of about 15-28% Ga.sub.2 O.sub.3 and 72-85% PbO. However, the preferred glasses contain up to 85% Bi.sub.2 O.sub.3 and consist essentially as included within the area generally encompassed by the curve in FIG. 2.

Abstract: Highly refractive, ThO.sub.2 -free optical glasses having refractive indices of 1.86-1.94 and Abbe-index numbers greater than or equal to 30, comprise:______________________________________ B.sub.2 O.sub.3 17-24 SiO.sub.2 0.5-6 B.sub.2 O.sub.3 + SiO.sub.2 19-27 La.sub.2 O.sub.3 40.1-51 ZrO.sub.2 5-9 Nb.sub.2 O.sub.5 0.5-25 Ta.sub.2 O.sub.5 0-27 Nb.sub.2 O.sub.5 + Ta.sub.2 O.sub.5 14-27 TiO.sub.2 0-8 PbO 0-12 ZnO 0-4 Al.sub.2 O.sub.

Abstract: The instant invention is directed to optical glass compositions capable of being shaped under the combined action of temperature and pressure in a mold so as to obtain articles having surfaces exhibiting highly precise reproduction of the mold walls. The inventive glasses demonstrate softening points not exceeding 500.degree. C., refractive indices between about 1.65-1.82, Abbe number between about 27-39, and consist essentially, in weight percent, of______________________________________ SiO.sub.2 8-20 B.sub.2 O.sub.3 5-20 PbO 50-70 Al.sub.2 O.sub.

Abstract: CdO- and ThO-free, highly refractive optical glass having a refractive index of 1.85-2.05 and an Abbe index of 25-43, characterized by the following composition (in percent by weight):______________________________________ SiO.sub.2 5-15 B.sub.2 O.sub.3 2.5-8 SiO.sub.2 + B.sub.2 O.sub.3 7-23 SiO.sub.2 /B.sub.2 O.sub.3 1.3-2.1 La.sub.2 O.sub.3 43-56 Gd.sub.2 O.sub.3 0-14 La.sub.2 O.sub.3 + Gd.sub.2 O.sub.3 43-60 ZrO.sub.2 3-10 Nb.sub.2 O.sub.5 0-15 Ta.sub.2 O.sub.5 0-20 Nb.sub.2 O.sub.5 + Ta.sub.2 O.sub.

Abstract: An optical glass comprising, in % by weight,18 to 38% P.sub.2 O.sub.5 ;3 to 30% Na.sub.2 O+K.sub.2 O,with the proviso of0 to 30% Na.sub.2 O and0 to 30% K.sub.2 O;8 to 65% PbO;1 to 45% Ta.sub.2 O.sub.5 ;0 to 20% Nb.sub.2 O.sub.5 ;0 to 15% TiO.sub.2 +WO.sub.3 ;0 to 25% BaO+CaO+ZnO+SrO+MgO,with the proviso of0 to 25% BaO,0 to 5% CaO,0 to 25% ZnO,0 to 20% SrO, and0 to 10% MgO;0 to 15% B.sub.2 O.sub.3 ;0 to 3% Li.sub.2 O;0 to 3% Al.sub.2 O.sub.3 ;0 to 3% ZrO.sub.2 ;0 to 3% Y.sub.2 O.sub.3 ;0 to 3% Gd.sub.2 O.sub.3 ; and0 to 3% La.sub.2 O.sub.3.

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: An improved optical glass having an index of refraction of .gtoreq.1.69, an Abbe number of .gtoreq.38, and a density of .ltoreq.3.25 g/cm.sup.3, represents a further development of another optical glass recently provided by the same inventors. The new glass has improved suitability for continuous-tank manufacture and increased acidproofness and differs from the other glass in its content of 0.5-4.0% by weight of P.sub.2 O.sub.5 ; its sum total of SiO.sub.2 +B.sub.2 O.sub.3 +Al.sub.2 O.sub.3 +P.sub.2 O.sub.5 being 38.5-41.5% by weight; and its sum total of MgO+CaO being 13-17.5% by weight. The full glass composition, e.g. is in % by weight:______________________________________ SiO.sub.2 26.0-32.5 B.sub.2 O.sub.3 6.0-12.0 Al.sub.2 O.sub.3 0-3.0 P.sub.2 O.sub.5 0.5-4.0 SiO.sub.2 + B.sub.2 O.sub.3 + Al.sub.2 O.sub.3 + P.sub.2 O.sub.5 = 38.5-41.5 Li.sub.2 O 0-5 Na.sub.2 O 0-6 K.sub.2 O 0-8 Li.sub.2 O + Na.sub.2 O + K.sub.2 O = 4.5-12.0 MgO 0-8 CaO 9-16 MgO + CaO = 13-17.

Abstract: An optical and ophthalmic glass having an index of refraction of .gtoreq.1.69, an Abbe number of .gtoreq.37, and a density of .ltoreq.3.30 g/cm.sup.3, consists essentially of (in % by weight):______________________________________ SiO.sub.2 18-36 B.sub.2 O.sub.3 3-18 GeO.sub.2 0-8 Al.sub.2 O.sub.3 0-6, wherein SiO.sub.2 + B.sub.2 O.sub.3 + Al.sub.2 O.sub.3 + GeO.sub.2 25-39 P.sub.2 O.sub.5 0-14, wherein SiO.sub.2 + B.sub.2 O.sub.3 + Al.sub.2 O.sub.3 + GeO.sub.2 + P.sub.2 O.sub.5 = 30-44 Li.sub.2 O 0-12 Na.sub.2 O 0-14 K.sub.2 O 0-18 Li.sub.2 O + Na.sub.2 O + K.sub.2 O = 2-18 MgO 0-15 CaO 7-25 MgO + CaO 15-32 SrO 0-13 BaO 0-17 ZnO 0-15 PbO 0-10 SrO + BaO + ZnO + PbO 0-20 TiO.sub.2 3-14 Nb.sub.2 O.sub.5 0-13 WO.sub.3 0-10 TiO.sub.2 + Nb.sub.2 O.sub.5 + WO.sub.3 = 10-21 ZrO.sub.2 0-15, La.sub.2 O.sub.3 0-20 Y.sub.2 O.sub.3 0-16 Gd.sub.2 O.sub.3 0-16 Yb.sub.2 O.sub.3 0-10 La.sub.2 O.sub.3 + Y.sub.2 O.sub.3 + Gd.sub.2 O.sub.3 + Yb.sub.2 O.sub.3 = 0-20 Ta.sub.2 O.sub.5 0-13 HfO.sub.2 0-5 SnO.sub.2 0-6.

Abstract: Glass microspheres and other glass elements based on B.sub.2 O.sub.3, BaO, SiO.sub.2 and TiO.sub.2 have an improved combination of crushing strength, index of refraction, and, especially in some formulations, chemical resistance. The microspheres are especially adapted for use as retroreflective elements in pavement markings.

Abstract: Glass compositions in the tin-phosphorus-oxyfluoride composition system exhibiting very low glass transition temperatures and capable of being modified by the addition of selected constituents to exhibit excellent stability in a humid environment, are described.