ABSTRACT
The temperature dependence of the cholesteric pitch, near a cholesteric to crystal smectic B transition, has been investigated. The cholesteric phase was induced by adding small amounts of a chiral component (CB-15) to a nematogenic compound (BCH-50), which also exhibits a crystal B phase. The main features of the resulting phase diagram are presented. A linear temperature dependence of the cholesteric pitch has been found. This behaviour is similar to that of cholesteric systems without any smectic transition. Thus, no pretransitional phenomena seem to occur during the cholesteric to smectic B transition.