Highly refracting optical glass for correction of high diopter values with low density

摘要: An optical quality glass suitable for use in eyeglass lenses, characterized by having a refractive index nd of at least 1.70; specific gravity not more than 3.0 and thermal coefficient expansion Alpha X 107 per *C 100, which contains 90 mol % metal oxide components molecular weight consists essentially SiO2, B2O3, Li2O, Na2O, K2O, MgO, CaO, ZnO, TiO2 crystallization stabilizing amount up to about 10 one member selected from the group consisting SrO, BaO, ZrO2, Ta2O5 Nb2O5.