Organic glasses and surface coatings are prepared, with short hardening cycles, by submitting to the action of U.V. light a liquid polymerizable composition containing at least one di-(allyl carbonate) or poly-(allyl carbonate) of a diol or polyol, a photoinitiator and a vinyl ester monomer and/or an organic peroxide. The composition can additionally contain small amounts of an organic compound selected from among those compounds which are used in the art in order to stabilize the organic polymers to the degrading action of U.V. light. The composition is preferably heated before being treated with U.V. iight.