Liquid Crystalline Properties and Photochromism of 4-Halogeno-N-(4-alkoxysalicylidene) anilines

Abstract

A new homologous series of 4-halogeno-N-(4-alkoxysalicylidene) anilines was synthesized. The phase transitions of these homologues were determined using a differential scanning calorimeter and an ordinary polarizing microscope. It is shown that the homologues exhibit liquid crystalline phases as the terminal alkoxyl chain is increased. A nematic phase is found for only a fluoro-derivative. All the other homologues show a smetic A phase. Furthermore, it is indicated that some members of these homologues series exhibit a photochromic property in the solid state.