Side-chain liquid crystalline and amorphous azobenzene-containing polymers are well known for the large photoinduced linear birefringence in them, and their potentialities for reversible optical storage and other optical applications. Here, we report on the inducement of large optical activity in films of a liquid crystalline azobenzene polyester, on illumination with circularly polarised light. The polyester has no chiral moieties and is initially isotropic. The induced optical rotation is up to 5 deg/μm at 633 nm, and 3 to 4 time larger at 488 nm The effect is explained in terms of the photoinduced reorientation of the rod-like chromophores, as well as by an angular momentum transfer from the circularly polarised light to the azobenzene side chains. This results in conformational changes in the whole polymer film.
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