A blend of epoxy and vinylester resins was crosslinked by using: 2-ethyl-imidazole with (PhCO)(2)O-2 or triethylene-tetraamine with AcEt hydroperoxide in Me-2 phthalate as mixed initiators at 120 degrees C for 2 h to study the curing course by differential scanning calorimetry and viscosity changes. Two sepd. exothermic effects were obsd.