Abstract: A process is disclosed for applying an adherent, optically clear, abrasion resistant coating to polycarbonate substrates such as lenses. The process includes: (a) forming a coating solution containing 25-75% of a hydrolyzed C.sub.1 -C.sub.2 alkyltri(lower alkoxy)silane, such as methyltriethoxysilane, in a water-miscible, volatile, organic solvent, and also containing small amounts of an abrasion-resistance enhancer and a stabilizing weak acid; (b) applying a thin, uniform coating of the coating solution to a clean surface of the polycarbonate substrate; and, (c) dehydrating the coated substrate under low humidity conditions at an elevated temperature below the temperature at which the substrate degrades until an adherent, abrasion resistant coating is formed.