Photopolymerizable compositions are provided which are the reaction products of a vinyl ether, a photoinitiator system comprising an iodonium salt, a visible light sensitizer, and an electron donor compound. These monomeric/oligomeric compositions may also include epoxides, polyols, spiroorthocarbonates. One embodiment of the present invention is a polymerizable composition comprised of a vinyl ether, a spiroorthocarbonate, and a photoinitiator system. Another embodiment of the present invention is a polymerizable composition comprised of a vinyl ether, an epoxide, a polyol, and a photoinitiator system. Still another embodiment of the present invention is a polymerizable composition comprised of a vinyl ether, an epoxide, a polyol, a spiroorthocarbonate, and a photoinitiator system. Still further, another embodiment of the present invention is certain novel spiroorthocarbonate compounds. Each of these novel spiroorthocarbonate compounds include at least one epoxy group as a substituent.