CELL ASYMMETRY CORRECTION FOR TEMPERATURE MODULATED DIFFERENTIAL SCANNING CALORIMETRY

The quality of measurement of heat capacity by differential scanning c alorimetry (DSC) is based on strict symmetry of the twin calorimeter. This symmetry is of particular importance for temperature-modulated DS C (TMDSC) since positive and negative deviations from symmetry cannot be distinguished in the most popular analysis methods. The heat capaci ties for sapphire-filled and empty aluminum calorimeters (pans) under designed cell imbalance caused by different pan-masses were measured. Tn addition, the positive and negative signs of asymmetry have been ex plored by analyzing the phase-shift between temperature and heat flow for sapphire and empty runs. The phase shifts change by more than 180 degrees depending on the sign of the asymmetry. Once the sign of asymm etry is determined, the asymmetry correction for temperature-modulated DSC can be made.