Photoinduced Anisotropy of IWK-2D Azobenzene Molecular Glassy Films

We have experimentally studied photoinduced anisotropy (PA) of holographic gratings in IWK-2D [precise chemical notation: 2-(3-(4-((4-(bis (2-(trityloxy) ethyl) amino) phenyl) diazenyl) styryl)-5,5-dimethylcyclohex-2-enylidene) malononitrile] azobenzene molecular glassy films in transmission and reflection modes using a special simultaneous holographic recording and readout setups which enabled measurements of PA time evolution. PA manifested itself by diffraction efficiency difference with linear s- and p-polarizations. Three different types of polarization holographic gratings were recorded and studied using p-p, L-L and L-R polarized beams creating different recording interference patterns. Atomic force microscope (AFM) was used to study the surface profile changes. Experimental evidence was obtained that the transmission mode PA was due to the both recorded surface relief and volume polarization gratings whereas the reflection mode PA was due to the recorded surface relief gratings. The main PA features were similar for all three types of polarization gratings whereas details were different. PA properties of IWK-2D films were notably distinctive from those of previously studied films.