DSC Characterization of Nematic-Smectic and Smectic-Smectic Phase Transitions in N(p-n-alkoxy benzilidene)-p-n-alkylanilines (n O. m)

ABSTRACT

The DSC method of Navard and Haudin is applied to characterize the liquid-crystalline phase transitions in a series of n O.m compounds, which exhibit rich but subtle polymorphism. This method involves the measurement of the ratio N = h₁/h (where h₁ and h are the heights of DSC transition peaks at two heating rates, one being twice the other). The particular relevance to distinguishing the order of the nematic-smectic A (NA) phase transition is emphasized.