Method of altering the visible absorption characteristics of permanently tinted photochromic glasses

摘要

A photochromic glass having colorant incorporated in the glass composition to impart a permanent tint, and having its chromaticity point shifted from the blue-green side toward the red side of the white point in the CIE chromaticity coordinate system, and a method of producing such article by heating the article for a sufficient time, and at a sufficient temperature, in a dilute, hydrogen-containing atmosphere to so move the chromaticity point.