THE DIELECTRIC BEHAVIOR OF GLASSY AMORPHOUS POLYMERS AT 2.45 GHZ

The dielectric behavior of glassy thermoplastic polymer in the microwa ve frequency range was investigated. Specifically, the relationship be tween energy absorption and temperature for several thermoplastic syst ems was examined to test the theoretical basis for heating under micro wave irradiation. Irradiation under traveling and standing wave condit ions were explored. The heating rate versus temperature data at a freq uency of 2.45 GHz yielded a microwave calorimetry procedure for examin ation of the dielectric and relaxation behaviors. Correlations were dr awn between (a) the apparent activation energy and the critical temper ature, and (b) the shape of the dielectric spectra at 2.45 GHz and its shape in the kHz region. WLF relationships were examined for glassy t hermoplastics to show the difference in changing activation energy wit h temperature.