Thermal lens scanning of the glass transition in polymers

In this article we discuss the use of the thermal lens technique for invest igating the thermal properties of polymers as a function of temperature. It is also discussed how the experimentally determined thermal lens parameter s can be used to locate the glass transition in polymers. The methodology i s tested using a solution casted films of poly(vinyl chloride) as a testing sample. A comparison with conventional differential scanning calorimetry d ata is made. It is proposed that the current transient thermal lens methodo logy, with minor changes in its experimental configuration, could be adapte d to develop a new methodology called differential thermal lens scanning es pecially designed for the investigation of the phase transitions in polymer s. It is shown that this new methodology could be equally used for the meas urement of the thermal expansion coefficient, above and below the glass tra nsition. (C) 2001 American Institute of Physics.