RAPIDLY FADING, HIGHLY REFRACTIVE INDEX PHOTOENANTIOTROPIC GLASS

摘要

PURPOSE: To reduce the change of photochromicity by making a photochromic glass contain SiO₂, B₂O₃, ZrO₂, Li₂O, Na₂O, Nb₂O₃, Ag, Br, Cl and CuO. ;CONSTITUTION: The composition of SiO₂: 43-52 wt.%, B₂O₃: 12.5-18 wt.%, Al₂O₃: 0-3 wt.%, ZrO₂: 3-8 wt.%, Li₂O: 1.5-3.5 wt.%, Na₂O: 0.3-3 wt.%, Nb₂O₅: 4-9 wt.%, MgO: 0-5 wt.%, CaO: 0-5 wt.%, SrO: 0.8-9 wt.%, BaO: 1-9 wt.%, K₂O: 2-9 wt.%, TiO₂: 2-8 wt.%, Ag: 0.100-0.175 wt.%, Cl: 0.140-0.350, Br: 0.093-0.180 and CuO: 0.0080-0.0300 for which 7X₂O12 where X₂O=Li₂O+K₂O, 2XO12 where XO=MgO+CaO+SrO+BaO, 12X₂O+XO20, 15ZrO₂+TiO₂+Nb₂O₅22, ZrO₂+Al₂O₃≤10, Nb₂O₅+Al₂O₃≤9, 0.15Li₂O/X₂O0.40, Ag+Br≥0.21 and Br+Cl0.24 is vitrified and this fast fading, high refractive index photochromic glass of a refractive index 1.585-1.610 and an Abbe number higher than 41 is obtained.;COPYRIGHT: (C)1991,JPO