The curing reaction of a thermosetting system measured by differential scanning calorimetry (DSC) requires a constant sample mass throughout the experiment. If one of the components is a volatile material, the weight loss and heat of volatilization should be taken into account. The simultaneous thermal analysis (STA) method provides simultaneous information of both weight and heat during the reaction. The actual heat of curing can be determined by subtracting the heat of volatilization from the heat of the curing reaction.