PHOTOCHROMIC ARTICLES AND THEIR METHOD OF MAKING

摘要

A photochromic article such as an ophthalmic lens has a substrate of a cross-linked organic polymeric matrix with a surface layer. The polymer in the surface layer is more porous than the polymer in the remainder of the substrate and the polymeric matrix in the surface layer contains a photochromic moiety. A method of making a photochromic article includes the steps of curing a cross-linkable pre-polymer to beyond a gel state to form a substrate of a partially cured polymeric matrix, inhibiting further curing of a surface layer of the substrate of partially cured polymeric matrix, and then incorporating an effective amount of a photochromic moiety into the surface layer either before or after substantially completely curing the remainder of the polymeric substrate.