Abstract
A photoresponsive chiral substituent consisting of dithienylethene moiety and chiral center was introduced into the side chain of bithienylene-phenylene copolymer. Reversible photoisomerization of the dithienylethene moiety was observed in both in CHCl3 solution and in cast film. Fluorescence of the polymer was quenched when the photochromic moiety changed from an open form to a closed one upon an irradiation of ultraviolet light. The quenched fluorescence was recovered through the reverse photoisomerization using visible light. Polarizing optical microscope demonstrated that the polymer has a main chain type liquid crystallinity. The polymer aligned by a rubbing technique exhibited a linearly polarized fluorescence (LPF). The cast film of the polymer showed Cotton effects in the region of pi - pi* transition of main chain in both circularly dichroism (CD) and circularly polarized fluorescence (CPF) spectra. The anisotropic fluorescence was controlled by the photochemical switching.
