Heat-darkenable photochromic glass - with lanthanum borate glass-phase contg silver halides and copper oxide

摘要

Photochromic heat-darkenable glass which can opt. take up and store information also under effect of visible light in which at least a part of a La borate glass-phase contains >=0.005 vol. % microcrystals of at least one of Ag halides, Ag chloride, Ag bromide or Ag iodide, as well as >=0.004 wt. % CuO, w.r.t. oxides and calculated in addn. to composn. contains in wt.% w.r.t. oxides, 15-75% La2O3, 13-65% B2O3, with >=35% La2O3 + B2O3 >=0.15% Ag, and 0.1% Cl, 0.1% Br and/or 0.1% I, with a wt. ratio Ag: halide >=1:1 to 4:1 and pref. 0.004-0.4 (more pref. 0.016-064)% CuO, 0.2-6% Ag and 0.2-1.5% Cl, 0.2-1.5% Br and/or 0.2-1.5% I (calc. in excess of glass composn.) and more pref., as stabilisers, in wt.% w.r.t. oxides, 0-40% Ta2O5. 0-40% Nb2O5, 0-15 % Al2O3, 0-45% ThO2, 0-15% TiO2, 0-15% ZrO2, 0-30% RO (where RO is ZnO, CdO, CaO, SrO, BaO, MgO and/or PbO).