Colored photochromic glasses and method
AssigneeCorning Glass Works
InventorsNicholas F. Borrelli, Brent M. Wedding
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Abstract
Surface-colored photochromic glass articles produced by reduction heat treatments at 450.degree. C. and below which exhibit induced absorption peaks at longer wavelengths than prior art glasses, and surface colors such as orange, red, purple and blue, are described.
Claims12
A colored silver halide-containing photochromic glass article exhibiting a surface coloration produced by the heat treatment of the photochromic glass article under flowing gaseous reducing conditions at a heat treatment temperature not exceeding about 450.degree. C., said colored photochromic glass article exhibiting, in at least one cross-sectional dimension in the undarkened state, a spectral transmittance curve comprising at least one treatment-induced absorption peak having a peak location to the right of the line CB of FIG. 1 of the drawing.
A method for producing a surface-colored photochromic glass article which comprises the step of heat-treating a silver halide-containing photochromic glass article under flowing gaseous reducing conditions at a temperature not exceeding about 450.degree. C. for a time at least sufficient to modify the surface light absorption characteristics of the article such that the article exhibits, in at least one cross-sectional dimension in the undarkened state, a spectral transmittance curve comprising at least one treatment-induced absorption peak having a peak location to the right of the line CB in FIG. 1 of the drawing.
Dependencies are inferred from the claim text.