Multilayered difiiision couples consisting of alternating layers of titanium (Ti) and amorphous silicon (a-Si) have been fabricated using sputter deposition with a range of modulation lengths corresponding to an average composition of Ti33 Si67. We have used differential scanning calorimetry to measure the enthalpy evolved during the solid state reaction a-Si + Ti → C49-TiSi2 and have characterized the phases formed using x-ray diffraction analysis. An average measured enthalpy of formation, ΔΗ was found to be ΔΗ = -58 + 9 kJ/g atom for thin film samples. Using scanning and isothermal calorimetry measurements, we have also characterized the kinetics involved during the initial intermixing stage.