Abstract: Described is an process for producing uniform coatings on circular substrates that reduces the amount of coating required. The improved process includes the steps of applying the liquid coating material through a single opening of a dispenser having certain characteristics, in a pattern onto the center of a spinning substrate, and then radially moving the dispenser opening near to the edge of the substrate while maintaining the dispenser opening at a predetermined distance from the substrate surface for substantially the entire radius of the substrate providing uniform coverage. Also described are products produced by the process that are substantially free of cosmetic defects and may be photochromic.

Abstract: Described are photochromic polyurethane coatings that meet commercially acceptable “cosmetic” standards for optical coatings. Also described are articles having such coatings. The coatings exhibit a Fischer microhardness of from 50 to 150 Newtons per mm2 and improved photochromic properties, i.e., the formation of darker activated colors and faster rates of photochromic activation and fade when irradiated with ultraviolet light.