Photoinduced Birefringence and Surface Relief Gratings in Polyurethane Elastomers with Azobenzene Chromophore in the Hard Segment

A series of polyurethane elastomers containing aromatic azobenzene chromophore in the hard segment was synthesized by a one-step method. AFM surface study showed that particles on the order of 100 nm to several micrometers appeared after annealing the polymer films. Birefringence was induced in these polymer elastomers. The stability of the photoinduced birefringence could be improved significantly by annealing the polymer films. This also …