The influence of temperature on the photopolymerization kinetics of three analogous monomers, 2,2’-thiobisethanol diacrylate, 2,2’-oxybisethanol diacrylate and 1,5-pentanediol diacrylate, has been studied by isothermal differential scanning calorimetry in the temperature range of 30-100 degrees C in air and in Ar atmosphere. The presence of the heteroatom markedly enhances the final conversion and maximum polymerization rate in air over the whole temperature range. This effect is much more pronounced for the sulfur-containing monomer. The final conversions of the monomers increase with temperature up to 100 degrees C in air but in Ar they pass through a maximum at about 70 degrees C in the case of monomers that do not contain sulfur. The sulfide group prevents the drop of cure extent in Ar at higher temperatures. The obtained results (kinetic parameters, activation energy) are discussed mainly in terms of hydrogen abstraction reaction.