PHOTOCONTROL OF ORIENTATION OF PHOTOCHROMIC DICHROIC DYES IN CHOLESTERIC POLYMER-FILMS

Strong LCICD (liquid-crystalline induced circular dichroism) was obser ved when a photochromic dichroic dye, 1, was doped into a cholesteric film of poly[(gamma-benzyl L-glutamate)-co-(gamma-dodecyl L-glutamate) ]. The ICD at the absorption band of anthraquinone changed its intensi ty reversibly when the azobenzene group was photoisomerized between ci s and Irans form. The phenomenon was interpreted in terms of an orient ational change of anthraquinone group associated with the photoisomeri zation of the azobenzene group. The structure-ICD relationship was inv estigated using several photochromic dichroic dyes with different anch oring groups on the azobenzene group and different spacers between the azobenzene and anthraquinone group.