Low Frequency Dielectric Relaxation Behaviour at the N-SA and SA-SC Transitions of 8S5

Abstract
It is shown that the dielectric relaxation time, connected with the reorientation about the short molecular axis, changes more or less continuously at the transitions: N-SA and SA-SC of 4-n-pentylphenyl-4′-n-octyloxy-thiobenzoate (8S5). Yet there is an evidence of pronouced steps in the intensity of the absorption at both transitions. The activation energy has about the same value in all liquid crystalline phases. It means that the SA and SC phases, having liquid like order within the layers, do not differ distinctly in molecular dynamics. However, the structure of both smectic phases has an impact on the dielectric increments.