High and stable photoinduced anisotropy in guest-host polymer mediated by chromophore aggregation.

We present a novel materials concept for optical inscription of stable birefringent optical elements into guest-host type polymers by making use of chromophore aggregation. The method is based on photoalignment of azobenzene chromophores, the aggregation of which leads to significant enhancement and stabilization of the photoinduced birefringence. The obtained order parameter of the molecular alignment (0.3) in combination with the exceptional thermal stability of the anisotropy renders the material system unique among amorphous azobenzene-containing polymers and provides a route toward designing efficient photoresponsive optical elements through the guest-host type approach.