Low-Frequency Dielectric Absorption in Organic Long-Chain Compounds due to the Presence of Traces of Alcohol Impurities

Abstract

IN recent investigations of the electrical properties of crystalline long-chain ketones and esters¹, considerable dielectric absorption has sometimes been observed at low audio-frequencies. This absorption appears to have electrical characteristics similar in all respects to the well-known low-frequency absorption which is usually attributed to ionic impurities or structural discontinuities, or a combination of the two (see, for example, ref. 2). The above measurements are now being extended to frequencies as low as 0.5 c./s., using a Schering bridge with a Lindemann electrometer as detector. The bridge is supplied with alternating potentials from a motor-driven sine–cosine potentiometer and 135-volt dry battery. Mercury electrodes with a clamped steel guard-ring are used, the electrode system being similar to, but smaller than, the one described by the Electrical Research Association³. Measurements of anomalous charging currents following the sudden application of a steady D.C. voltage are also being made, using the Lindemann electrometer in the way described by Doust and Sulston⁴. When possible, the steady-state D.c. conductivity (σdc) has also been obtained from the same readings.