Abstract: A fluorine containing silicate glass substrate is heated to a temperature sufficiently high to permit fluorine to out-diffuse from the surface thereof. A surface region is formed having a gradient fluorine concentration in a direction perpendicular to the substrate surface, the region of lowest fluorine concentration having the highest refractive index. The resultant device is capable of functioning as an optical waveguide.

Abstract: The instant invention is concerned with transparent photochromic glass compositions which not only exhibit desirably rapid darkening and fading characteristics, but which also demonstrate the other physical and optical properties required for use in ophthalmic applications. Such glasses utilize the presence of silver chloride and/or silver bromide crystals to impart photochromic behavior in a narrowly-defined composition range within the alkali metal aluminoborosilicate base system. Copper ions are also included in the composition to perform as a sensitizing agent. The glasses have the capability of being either thermally tempered or chemically strengthened to comply with the United States Food and Drug Administration regulations for lenses used in ophthalmic applications. Improved independence of temperature effects upon the photochromic properties can be achieved where the copper level, expressed as CuO, is maintained between about 0.004-0.

Abstract: A process for the production of a gradient photochromic glass article comprising the selective over-nucleation of a limited portion of the article followed by a photochromic development heat treatment of the entire article, and the product of this process, are described.

Abstract: Chemically-strengthenable silver halide-containing lithium boroaluminosilicate glass compositions having physical and chemical characteristics required for sheet drawing processes and exhibiting excellent photochromic properties after heat treatment, and also strengthened photochromic drawn sheet glass articles provided therefrom, are described.

Abstract: The instant invention is related to the manufacture of photochromic glasses having base compositions within a very narrow interval of the alkali metal boroaluminosilicate system wherein silver chloride and/or silver bromide crystals impart photochromic properties. The glasses are notable for their rapid fading characteristics and relatively low temperature dependence of darkening. The compositions are especially suitable for a production process which contemplates simultaneously shaping articles from glass sheet and developing photochromic properties therein.

Abstract: Silver halide-containing photochromic glasses are rendered optically anisotropic by darkening with actinic radiation and irradiating with linearly polarized bleaching light. A photochromic glass so treated will be optically isotropic when it returns to the clear state, but may again become optically anisotropic when redarkened. Color adaptation results when darkened silver halide-containing photochromic glasses are irradiated with colored optical bleaching light.

Abstract: The absorptive and refractive properties of additively colored glasses containing an absorptive metallic silver phase and a separated silver halide phase are altered by irradiating the colored glasses with visible light. Polarization effects and multicolored images can be produced.

Abstract: A method and system for processing a photographic negative to obtain photographic prints exhibiting enhanced contrast therefrom are described. A sheet of darkened optically bleachable photochromic glass, positioned between the negative and a selected photographic printing medium, is selectively bleached by light passing through the negative to form an image of the negative in the glass. Light of a wavelength effective to activate the photographic printing medium is then passed through the photographic negative and selectively bleached photochromic glass and focused to provide an enhanced contrast image of the photographic negative on the printing medium. A photographic print of enhanced contrast is thus produced.

Abstract: Chemically-strengthenable silver halide-containing lithium boroaluminosilicate glass compositions having physical and chemical characteristics required for sheet drawing processes and exhibiting excellent photochromic properties after heat treatment, and also strengthened photochromic drawn sheet glass articles provided therefrom, are described.

Abstract: A fluorine containing silicate glass substrate is heated to a temperature sufficiently high to permit fluorine to out-diffuse from the surface thereof. A surface region is formed having a gradient fluorine concentration in a direction perpendicular to the substrate surface, the region of lowest fluorine concentration having the highest refractive index. The resultant device is capable of functioning as an optical waveguide.

Abstract: Silver-free photochromic glasses capable of reversibly changing from the clear nonpolarizing state to the darkened polarizing state are provided by heating a photochromic alkali boroaluminosilicate base glass containing copper and/or cadmium halides to a working temperature and elongating the glass to modify the photochromic particles therein.