A NEW APPLICATION OF THE NONLINEAR DIELECTRIC METHOD FOR STUDYING RELAXATION PROCESSES IN LIQUIDS

The measurement setup for studying changes of electric permittivity in duced in liquids by a strong electric field nonlinear dielectric effec t, (NDE) is presented. The construction is based on the idea of freque ncy modulation of an LC generator (with an inductance L and a capacita nce C in resonant circuit), proposed by Malecki [J. Chem. Soc. Faraday Trans. II 72, 104 (1976)]. The strong electric field is applied in th e form of rectangular pulses (typically 1-4 ms). The setup enables mea surements in a broad range of frequencies (80 kHz-12 MHz) and contains a new calibrating system, minimizing the influence of systematic erro r on the measured NDE values. We also indicate menthol as a standard, reference liquid in NDE studies. New applications of the NDE technique for studying relaxation processes in critical solution are also prese nted. They are based on the time resolved analysis of NDE decay after switching off the strong electric field. (C) 1996 American Institute o f Physics.