Corning Incorporated
PHOTOCHROMIC GLASS AND PHOTOCHROMIC GLASS WINDOWS

Abstract:

A photochromic glass, comprising: (i) a glass matrix that, comprising in mol percent (mol %) based on oxides: 66 mol %.ltoreq.SiO.sub.2.ltoreq.75 mol %; 8 mol %.ltoreq.B.sub.2O.sub.3.ltoreq.13 mol %; mol %.ltoreq.Al.sub.2O.sub.3.ltoreq.7 mol %; 1.5 mol %.ltoreq.P.sub.2O.sub.5.ltoreq.6 mol %, mol %.ltoreq.Na.sub.2O.ltoreq.5.5 mol %; 3 mol %.ltoreq.K.sub.2O.ltoreq.9.5 mol %; 0 mol %.ltoreq.MgO.ltoreq.4 mol %; 0 mol %.ltoreq.Li.sub.2O.ltoreq.0.05 mol %; 0 mol %.ltoreq.BaO.ltoreq.0.05 mol %; 0 mol %.ltoreq.CaO.ltoreq.0.05 mole %; wherein the amount of (Li.sub.2O+BO+CaO.ltoreq.0.1 mole %); and (ii)) a plurality of photochromic agents, comprising in mol percent (%) with respect to the glass matrix: 0.07%.ltoreq.Ag.ltoreq.0.15%; 0.14%.ltoreq.Cl.ltoreq.0.25%; 0.025%.ltoreq.Br.ltoreq.0.04%; 0.0065%.ltoreq.CuO.ltoreq.0.015%, and wherein CuO/Ag.ltoreq.0.22.