Vulcanization reaction was studied by DSC through the comparison cure states to physical properties and the investegation of chemicals effect on vulcanization. Reaction enthalpy showed a good correlation with physical properties, increased with the increase of sulfur content, and increased with accelerator content, as well, where the ratio of MOR to sulfur was less than 1.0. Reaction temperature was decreased with increasing accelerator content and decreased also with sulfur content where the ratio of MOR to sulfur was more than 1:3. As a result, the cure state and reaction temperature could be controlled effectively with the ratio of accelerator to sulfur in the range of a third to unity.