Phototunable azobenzene

Azobenzene systems represent very attractive phototriggers in Ch LCs, thanks to their resistance to photofatigue, the simplicity of the molecules, and the ease of modification of their molecular structures. This chapter first describes helical twisting ability of chiral azobenzene compounds by focusing the structural effects on HTP as well as photochemical change in HTP, and then phototuning of helical structures of Ch LCs through the trans-cis photoisomerization of the chiral azobenzene compounds for applications to optical devices. 

This section discusses the photochemical switching of selective reflection, transparency, helical sense, and lasing through the phototuning of helical structure of the Ch LCs by photoisomerization of chiral azobenzene compounds. 

S.V. Serak, N.V. Tabiryan, G. Chilaya, A. Chanishvili, G. Petriashvili, Chiral azobenzene nematics phototunable with a green laser beam. Mol. Cryst. Liq. Cryst. 488, 42-55 (2008)... 

Diarylethene Dopants In the reversible phototuning of reflection color in CLCs using azobenzenes or overcrowded alkenes, all the photoresponsive dopants experienced photoisomerization but were accompanied by competing thermal back relaxation. For example, azobenzenes can transform from the trans form to the cis form... 

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