Method for making polarizing glasses by extrusion

Abstract

The instant invention is directed to the production of highly polarizing glasses, i.e., the glasses exhibit dichroic ratios up to 40 and higher, from silver-containing glasses that are characterized as being phase separable or, more preferably, as being photochromic because of the presence of silver halide particles therein, i.e., particles selected from the group of AgCl, AgBr, and AgI. The inventive method contemplates two general steps: (a) the glasses are elongated under stress such that the glass phases and/or silver halide particles are elongated and aligned in the direction of the stress; and (b) the elongated glasses are heat treated in a reducing environment at temperatures below the annealing point of the glass but above about 300.degree. C. to reduce a portion of the silver ions in the glass to metallic silver which is deposited in at least one of the glass phases and/or along the phase boundaries of the glass phases and/or deposited upon the silver halide particles.

Dependencies are inferred from the claim text.