Thermal and photo optical properties of azoxybenzene/alkyloxy-ambenzene-cholesterol dimesogens with alkyl diacetylene linker

Thermal and photo-optical properties of azoxybenzene/alkyloxy-azobenzene containing chiral dimesogens are presented. Alkyloxyazobenzene containing dimesogenic materials exhibited two kinds of smectic A phases. Photoirradiation at temperatures exhibiting, smectic phases of pure materials in azobenzene linked dimesogens resulted in formation of the isotropic phase, and this was systematically studied at different liquid crystalline temperatures. The efficacy of these compounds as a dopant in the glassy liquid crystalline material was also explored. Increasing concentration to 4 wt%/5 wt% in azobenzene/azoxy-benzene derivatives caused a dramatic red-shift in the wavelength of reflected light by the host cholesteric glassy liquid crystal. Photo-isomerization of these dopants led to a blue-shift of the reflected light, and this effect could be used to tune the light reflectivity of these mixtures over the visible region.