The use of in situ Raman spectroscopy is reported as a tool for probing the effects of microwave irradiation on molecules. Our results show no evidence for localized superheating, an often-cited specific microwave effect. While the microwave energy may interact with the polar molecules more so than with non-polar ones, the conversion of electromagnetic energy into kinetic energy is slower than conversion of kinetic energy into thermal energy. As a result, more polar molecules are not at a temperature greater than that of the bulk.