Time stability of photoinduced birefringence in amorphous and liquid-crystalline azopolymers

L Nedelchev, D Nazarova
2013 Bulgarian Chemical Communications   unpublished
One of the most important parameters for every optical data storage media is the stability of the recorded information in time. When polarization holography is used for data recording, the information is encoded via the photoinduced anisotropy (most often birefringence) in the media. In this article we present a study on the stability of the photoinduced birefringence (Δn) in amorphous (P 1) and liquid-crystalline (LC) azobenzene polymer (P 2) with similar structures of the backbone and the
more » ... ackbone and the chromophore unit, but different spacers between them. As our experiments indicate, 72 % of the photoinduced birefringence is retained in the polymer P 1 , and 104 % in the polymer P 2 one hour after the end of the recording process i.e. the stability of the birefringence in the LC polymer is considerably higher than in the amorphous.