The effect of new additives on the thermal conversion of a range of polyamic acids to polyimides at temperatures lower than 100 degrees C was investigated using infrared spectroscopy. Additives such as m-hydroxybenzoic acid, p-hydroxyphenylacetic acid, and p-hydroxybenzenesulfonic acid were found to be highly effective as curing catalysts or accelerators. The degree of imidization of polyamic acids in the presence of additives increased with an increase in the reaction temperature, and complete imidization was achieved at 140-200 degrees C. The reaction was characterized by a rapid rate that slowed with time.