In photolysis of tetrafluoroethylene in a solution of the hexafluoropropylene trimer containing long-lived perfluoroallyl radicals, the following processes can take place: 1) phototransformation of these radicals into active perfluoroalkyl radicals and their recombination, and participation in initiation of photopolymerization of tetrafluoroethylene; the formation of the long-lived perfluoroalkyl radical on addition of a molecule of solvent to the propagating radical and the formation of a long-lived radical captured by the propagating chain compete with these processes.