Thermal diffusivity of a hard boiled candy obtained by photothermal beam deflection and standard photopyroelectric method

摘要

Two different photothermal techniques, the photopyroelectric (PPE) detection and photothermal beam deflection (PTBD) method, were used for the thermal characterisation of a glassy sugar system, commercially available hard boiled candy. Thermaldiffusivities (at room temperature) obtained are comparable (i.e. 14.7×10{sup}-8 and 12.0×10{sup}-8 m{sup}2s{sup}-1 for PPE and PTBD respectively).In addition, the PPE technique was also used to measure temperature dependence of the thermal diffusivity in the -30℃ to 70℃ temperature range. The glass-rubber transition, underwent by the sample in this temperature range was observed and compared tothat obtained by differential scanning calorimetry (DSC).