Strengthened polychromatic glasses

摘要: This invention is concerned with the production of chemically strengthened polychromatic glasses. In preferred embodiment, glasses are suitable for ophthalmic applications, i.e., have a refractive index at least 1.523 and, after chemical strengthening, will exhibit surface compression layer having depth 0.002", maximum central tension 0.7 kg/mm 2 , and modulus rupture approximately 30,000 psi such as to pass FDA strength requirements glass lenses. For this strengthening reaction be conducted period not exceeding about 24 hours compositions consisting essentially, by weight on oxide basis calculated from batch 11-18% Na O, 60-70% SiO 3-12% ZrO 0-18% ZnO and/or 0-14% Al O 3 total ZnO+Al 20%, 0-5% BaO, 0.005-0.3% Ag, 0.01-0.2% CeO 1-4% F, an amount one halide selected group Cl, Br, I sufficient react stoichiometrically but more than 3%.