Described is a polymerizable composition of a photochromic amount of at least one photochromic compound, at least one material having at least one carbonate group and at least one hydroxyl group, and at least one monoisocyanate containing material having at least one unsaturated group. The polymerizable composition optionally contains copolymerizable monomers. Also described are photochromic polymerizates, e.g., photochromic optical elements such as ophthalmic lenses, prepared from the polymerizable composition of the present invention.