Abstract
The thermal properties for a homologous series of 4-(4-alkoxyphenoxycarbonyl)phenyl 5-cyano-2-furancarboxylates have been examined. The smectic A phase commences from the hexyloxy homolog, and the octyloxy, nonyloxy and decyloxy homologs show two kinds of smectic A phases and experience the SA-SA transition. The lower phase which shows a typical fan shaped texture is assigned to a smectic A with a bilayer arrangement of the molecules (SA2). The higher phase which shows a typical fan shaped texture on the cooling stage and a broken fan one on the heating stage, is assigned to a smectic A with a partially bilayer arrangement of the molecules (SAd). The SA-SA transitions could be easily detected by both differential scanning calorimeter and optical microscopic method.