Method of making polarizing glasses

Abstract

Polarizing glass articles and methods of manufacturing polarizing glass articles are disclosed. The method involves forming a polarizing layer on the surface of the glass article by ion-exchanging silver or copper into the surface.

Description

FIELD OF THE INVENTION [0001] This invention relates to polarizing glasses. More particularly, the invention relates to methods of making polarizing glasses and polarizing articles such as optical isolators made from such glasses. BACKGROUND OF THE INVENTION [0002] Several methods are known for making polarizing glasses. For example, it has been demonstrated that polarizing glasses can be produced from silver halide-containing glasses by a redraw process as disclosed in U.S. Pat. No. 3,540,793 (Araujo et al.), or by subjecting stretched glass to a reducing gas atmosphere as disclosed in U.S. Pat. Nos. 4,304,584 and 4,479,819 (Borrelli et al.). In the redraw process, glass containing a separable phase is stretched or redrawn above its softening temperature, during which process, the separable phase is elongated. The thermal treatment which leads to the phase separation is carried out before the redraw process. In one version of the above process, the separated phase is initially spec...

AI Technical Summary

Benefits of technology

This approach reduces light scattering and enhances transmission by concentrating silver or copper metal in the surface layers, achieving higher concentrations than conventional methods and minimizing halide presence in the central layer, thus improving the performance of polarizing glass articles like optical isolators.

Problems solved by technology

Also, when the polarizing glass is heated to the vicinity of 500° C. for any prolonged period of time, the elongated particles respheroidize and the polarizing property is lost.

For certain applications, particularly telecommunications applications, one disadvantage of manufacturing polarizing glass elements by the methods referenced above is that phase-separated silver halide phase remains in the central layer of the glass element after the outer layer has been reduced to elemental silver.