US Patent 7666331 Photochromic article

Describes an article, e.g., an optical article such as a lens, in which the article includes (a) a rigid substrate, e.g., a transparent ophthalmic substrate, such as a thermoset or thermoplastic substrate, having at least one surface suitable for accommodating a photochromic coating, and (b) a transparent photochromic coating comprising dendritic polymeric acrylate, e.g., polyester acrylate, on at least a portion of said surface of the substrate, the coating comprising a photochromic amount of at least one photochromic material, e.g., an organic photochromic material.