Epoxides bearing vinyl groups bonded to one of the carbon atoms of the three-membered ring, exhibit the ability to dramatically increase the rate of the photoinitiated cationic polymerization of 3-mono- and 3,3-disubstuted oxetanes by eliminating or sharply reducing the length of the induction periods. This effect, termed by us as "kick-starting", results from the ability of the aforementioned epoxides to undergo ring-opening on protonation to yield resonance stabilized allylic carbocations. Several examples are given of "kick-starting" epoxides together with their use in the photopolymerization of various oxetane monomers. (C) 2015 Elsevier Ltd. All rights reserved.