A process for the preparation of a glass object, which in the case of irradiation with uv rays - strongly fluoresces

摘要

A glass which fluoresces when exposed to U.V. radiations of 300-400 mm consists essentially, in per cent by weight of: SiO2, 35-70; R2O, 3-29; the total of the preceding components being at least 54%; and Al2O3, 0-25; B2O3, 0-15; R1O, 0-5; CuO, 0-0.02; CeO2 0-0.2; Sb2O3, 0-0.5; CoO, 0-0.005; NiO, 0-0.05. Also present may be 2-3% F., 1.2% Cl, and 0.67% Br. At least a surface-layer of the article further contains 0.2-1.0% colloidal Ag particles. The article fluoresces strongly when exposed to 300-400 mm U.V. light. R2O is Li2O, 0-20; Na2O, 0-25; and K2O, 0-25; R1 is Mg, Ca, Ba, Cd and/or Zn. The article may be prepared by forming a glass body of the above composition, cooling the melt to form a shape, and heat-treating at 300-450 DEG C. while exposing to U.V. radiations of 280-340 mm ; a fluorescent pattern may be produced by placing a masking stencil on the body during this U.V. treatment. In an ion-exchange process which forms a modification of the invention, glass of the above composition but without Ag is exposed to a hot silver paste or silver bath to form a fluorescent surface layer.ALSO:A glass which fluoresces when exposed to U-V radiations of 300-400 mm consists essentially, in per cent by weight of: SiO2, 35-70; R2O, 3-29; the total of the preceding components being at least 54%; and Al2O3, 0-25; B2O3 0-15; R1O, 0-5; CuO, 0-0.02; CeO2, 0-0.2; Sb2O3, 0-0.5; CoO, 0-0.005; NiO, 0-0.05. Also present may be 2-3% F, 1.2% Cl, and 0.67% Br. At least a surface-layer of the article further contains 0.2-1.0% colloidal Ag particles. The article fluoresces strongly when exposed to 300-400m m U-V light. R2O is Li2O, 0-20; Na2O, 0-25; and K2O, 0-25; R1 is Mg, Ca, Ba, Cd and/or Zn. The article may be prepared by forming a glass body of the above composition, cooling the melt to form a shape, and heat-treating at 300 DEG -450 DEG C. while exposing to U-V radiations of 280-340 mm ; a fluorescent pattern may be produced by placing a masking stencil on the body during this U-V treatment. In an ion-exchange process which forms a modification of the invention, glass of the above composition but without Ag is exposed to a hot silver paste or silver bath to form a fluorescent surface layer.