Measurement of the thermal diffusivity of thin films by an AC joule-heating method

A new thermal analysis narned TWA ITemperaturc Wave Analysis) is proposed. This technique is based on the AC joule-heating method developed in our laboratory, and makes it possible to obtain thermal diflʹt,s ivity precisely as a function of temperatttre at a constant frequency. The theoretical background and the calculation procedure for this technique arc reported. This technique was applied to the study of the lirst order transition of high density polyethylene and the glass transition of glycerin.