Stability can be studied using batch, scanning, and flow calorimetry.  In this example a compound was studied using gas flow microcalorimetry.  First argon was passed over the sample for 6 hours at 80 C to determine thermal contributions other than oxidation.  The gas flow was switched to oxygen and a significant exotherm was observed.  Measurement of the heat flow after steady state conditions are met, at different temperatures, makes it possible to determine the activation energy.