Abstract
The spectroscopic features and photoisomerization behaviors of chiral photochromic 3,3′-dialkoxyazobenzenes were evaluated in an isotropic solution and a nematic solvent. The effect of photoisomerization on the helical twisting power and handedness of these chiral dopants in induced cholesteric liquid crystals were studied. Depending on the distance of the chiral center from the azo-core, elongation of the helical pitch and reversion of the handedness upon E-to-Z photoisomerization were observed. These characteristics are interesting for optical devices based on light-controlled phase switching.