Cross-linked polymers were obtained by photopolymerization of epoxidized linseed oil with different reactive diluents (3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate, 1,4-cyclohexane dimethanol diglycidyl ether, bisphenol A diglycidyl ether, trimethylolpropane triglycidyl ether, and bis[4-(glycidyloxy)phenyl]methane) using the mixture of triarylsulfonium hexafluoroantimonates as photoinitiator. The kinetic of photocross-linking reactions of compositions with different concentrations of reactive diluents was investigated. The 69%-91% conversion of epoxy groups of the compositions containing reactive diluents was reached. The mechanical properties, thermal stability, and swelling in polar and nonpolar solvents of the photocross-linked polymers were studied.