The relative permittivity transition in solid camphor

Three-terminal measurements of capacitance and dissipation factor have been made on samples of d-camphor, dl-camphor and l-camphor at frequencies between 200 Hz and 10 kHz over the temperature range -196 degrees C to +20 degrees C. The dielectric relaxation processes in d-camphor, below the transition temperature, have been studied and the change in the frequency of maximum dielectric loss, which occurs during the transition, has been estimated. It is believed that these results are the first to provide direct evidence of the increased freedom of molecular rotation which occurs during the transition. Electrical conduction appears to commence immediately on completion of the transition and increases with increasing temperature.