Synthesis and photorefractivity of 2-{4-[4-(6-carbazol-9-yl-hexyl)-piperazin-1-yl]-benzylidene}-malononitrile

The present article describes the synthesis and characterization of amorphous low molecular weight glasses via flexible covalent bonds with hexyl-group, 2-{4-[4-(6-carbazol-9-yl-hexyl)-piperazin-1-yl]-benzylidene}-malononitrile (Cz-C6-DCST). At room temperature, this molecule forms a stable amorphous glassy material which exhibits a low Tg (40 °C) and no crystallization based on our DSC experiments. The films prepared from CH2Cl2 solutions containing 1 wt% TNF and 10 wt% N-ethylcarbazole are transparent and of excellent optical quality. The 50 μm thick film showed the maximum diffraction efficiency of 78.5% at 70 V/μm.