Enhanced stability of photo-induced anisotropy due to intermolecular interactions in an azo-prepolymer confined in block copolymer

Many efforts in the field of azobenzene-containing polymers are concentrated on exploring new material concepts to obtain efficient and stable photo-induced anisotropy. Here, an easy approach to improve the birefringent properties of an epoxy-based azo-prepolymer is reported. The designed azo-prepolymer was selectively confined in a self-assembled domain of a block copolymer and thanks to the formation of hydrogen bonds a major enhancement of its optical response was achieved. In particular, the resulting material presented double the maximum level of optical anisotropy of the neat azo-prepolymer and nearly 80% of remaining birefringence.