Abstract: The present invention relates generally to UV (ultraviolet) photosensitive bulk glass, and particularly to batch meltable alkali boro-alumino-silicate glasses. The photosensitive bulk glass of the invention exhibits photosensitivity to UV wavelengths below 250 nm. The photosensitivity of the alkali boro-alumino-silicate bulk glass to UV wavelengths below 250 nm provide for the making of refractive index patterns in the glass. With a radiation source below 250 nm, such as a laser, refractive index patterns are formed in the glass. The inventive photosensitive optical refractive index pattern forming bulk glass allows for the formation of patterns in glass and devices which utilize such patterned glass.

Abstract: The instant invention is directed to the preparation of glass articles exhibiting excellent polarization in the infrared portion of the spectrum from glasses characterized as containing silver halide particles therein selected from the group of AgCl, AgBr, AgI. The inventive method comprises four general steps:(a) a batch for a glass containing silver and at least one halide selected from the group of chloride, bromide, and iodide is melted and the melt shaped into a glass body of a desired geometry;(b) the glass body is subjected to a heat treatment at least above the strain point but not in excess of 50.degree. C. above the softening point of the glass for a period of time adequate to cause the generation of AgCl and/or AgBr and/or AgI particles therein, said particles ranging in size between 200-5000 .ANG.;(c) the glass body is elongated under stress at temperatures above the annealing point, but below that where said glass exhibits a viscosity of about 10.sup.