Importance

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Abstract

Organic photochromic materials comprising a photochromic dye and a resinous material can be stabilized with a protective coating which will protect them from deactivation by exposure to moisture, oxygen, various plastic host materials, reactive chemicals or even normal atmospheric conditions. Useful organic photochromic dyes include the spiropyrans, the spirooxazines, the metal dithizonates, the phenazines, the phenothiazines and other known photochromic compositions. Useful resinous materials include vinyl-type thermoplastics, cellulosic materials, polyesters, epoxy resins and aminoplast resins. The encapsulated photochromic materials of the invention comprise an organic photochromic dye in combination with an organic resinous material enclosed within an outer shell of an inorganic material and find use in the preparation of photochromic plastic films, sheets, ophthalmic lenses such as lenses for sunglasses and in camera lenses and filters.

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First Claim