Kinetic stabilisation of the polar smectic-A phase of cyclic siloxane oligomers

Cavendish Laboratory, University of Cambridge Madingley Road, Cambridge CB3 0HE, UK

Received: 9 September 1998
Accepted: 22 February 1999

Abstract

We propose a simple model for the decay of field-induced polar order in the smectic-A liquid crystal phase of a new cyclic siloxane oligomer (E. T. Samulski et al., Nature 384 (1996) 244). Experimentally the polarisation is seen to drop abruptly at short times but then remain fairly constant at a large non-zero value. We explain this apparent plateau as a consequence of the jamming of relaxation by a long-lived intermediate molecular conformation. Our results can be made to agree with experiment using essentially one fitting parameter, which can also be independently measured as the timescale for the decay of the polarisation of the linear siloxane oligomer.