HIGH-PRECISION HEAT-CAPACITY MEASUREMENT BY DYNAMIC DIFFERENTIAL SCANNING CALORIMETRY

We developed a novel method for measuring heat capacity with high prec ision by use of the modulated mode (or ac mode) in dynamic differentia l scanning calorimetry (dynamic DSC). For this purpose, we placed a pa n with a sample on the sample side and no pan on the reference side. T he thermal system was analyzed, taking into account a thermal resistan ce between the sample pan and the base plate; this quantity is indispe nsable in dynamic measurements such as differential scanning calorimet ry and dynamic DSC, but is difficult to estimate. From the theoretical analysis, it was found that the calibration constant required for hea t capacity determination is strictly given in terms of a relation of t he amplitude ratio of ac temperatures vs their phase difference even i f there is the thermal resistance.