Temperature range of the smectic-Aphase and its effect on the smectic-A–smectic-Ctransition

Abstract
X-ray studies on a material whose constituent molecules have a weak transverse dipole moment provide clear evidence of a first-order smectic-A–smectic-C transition. In addition, results on materials belonging to the same homologous series of compounds show that this transition can be driven from second order to first order simply by reducing the temperature range of the smectic-A phase.