Cyclic acetals were used as a second co-initiator in three-component photoinitiating systems. The mixtures of cyanine dye borate ion salt and cyclic acetals were used to initiate the visible light polymerization of triacrylate monomer (TMPTA). The kinetics of polymerization was recorded by differential scanning calorimetry (DSC). The results showed that the addition of cyclic acetals increases the rate of polymerization (R (p)).