Patent ID: 7618908

Claim:
A visible light optical polarizer made by a process comprising: preparing a glass melt batch containing a non-halide silver salt, the amount of the silver salt in the melt being sufficient to produce a glass having a silver content in the range of 0.05-1.0 wt % calculated as silver(0); preparing a glass form suitable for drawing into a ribbon; treating the glass form in a reducing atmosphere for a time in the range of 25-100 hours and a temperature below the softening point of the glass, wherein the reducing atmosphere is hydrogen; stretching the glass form into a ribbon having a polarizing layer containing elongated silver(0) particles using any method known in the art; polishing the ribbon; and cutting the ribbon to the desired size to thereby form the visible light optical polarizer; wherein the treatment in the reducing atmosphere is carried out after the melt has been cast into a form and before the form is stretched into a ribbon, and the glass composition has a halide content that is, on a molar basis, 10% or less than the silver content of the glass.