C. Ruslim et al., Chiroptical properties of cholesteric liquid crystals induced by chiral photochromic 3,3 '-dialkoxyazobenzenes, MOLEC CRYST, 365, 2001, pp. 1011
The spectroscopic features and photoisomerization behaviors of chiral photo
chromic 3,3'-dialkoxyazobenzenes were evaluated in an isotropic solution an
d a nematic solvent. The effect of photoisomerization on the helical twisti
ng power and handedness of these chiral dopants in induced cholesteric liqu
id crystals were studied. Depending on the distance of the chiral center fr
om the azo-core, elongation of the helical pitch and reversion of the hande
dness upon E-to-Z photoisomerization were observed. These characteristics a
re interesting for optical devices based on light-controlled phase switchin
g.