Temperature calibration in dielectric measurements

Dielectric experiments are often performed in non-isothermal conditions. Thus, there is a difference between the temperature of the sample and the sensor temperature. In this work we propose and compare three temperature calibration methods based on the detection of transitions or relaxations: i) the melting of high-purity metallic standards (indium and tin), ii) the 2(nd) order phase transition of a ferroelectric crystal (TGS); iii) the alpha -relaxation of an amorphous polymer (poly(carbonate)). The results obtained from the three different methods were used to construct a calibration curve for a given heating rate.Fundação para a Ciência e Tecnologia - PRAXIS/P/CTM/14171/1998, PRAXIS/P/QUI/10071/1998