NEW LMM ORGANOSILOXANES WITH PHOTOISOMERISING AZO GROUPS

A new LMM photo-reactive chiral ate-containing organosiloxane (C(10)Az oB) and its racemic analogue (C(10)Azo(+/-)B) have been synthesised a nd their mesomorphic properties investigated. The materials are denote d C(10)AzoB and C(10)Azo(+/-)B where C-n refers to the number of meth ylene units in the alkyl spacer, Azo and Azo(+/-) denote the chiral a nd racemic photoisomerising azobenzene-based mesogenic moiety and B re fers to the pentamethyldisiloxane tail. Both LMM siloxane derivatives exhibit a single enantiotropic smectic A phase. Results on the consequ ences of incorporating these new materials into a related fast switchi ng, LMM ferroelectric organosiloxane host will be given. In addition r esults will be presented on the photoisomerisation of the azo material s and their use in optically manipulating the magnitude of spontaneous polarisation in a ferroelectric liquid crystal.