Prasad V. Liquid crystalline compounds with V-shaped molecular structures: synthesis and characterization of new azo compounds [J]. Liq. Cryst., 2001, 28(1):145-150.[2] Jkli A, Prasad V, Shankar Rao D S, et al. Light-induced changes of optical and electrical properties in bent-core azo compounds [J]. Phys. Rev. E, 2005, 71(1):021709-021715.[3] Prasad V, Kang S W, Qi X H, et al. Photo-responsive and electrically switchable mesophases in a novel class of achiral bent-core azo compounds [J]. J. Mater. Chem., 2004, 14 (9):1495-1502.[4] Lutfor M R, Hegde G, Kumar S, et al. Synthesis and characterization of bent-shaped azobenzene monomers: Guest-host effects in liquid crystals with azo dyes for optical image storage devices[J]. Opt. Mater., 2009, 32(1):176-183.[5] Blinov L M. Photoinduced molecular reorientation in polymers, Langmuir- Blodgett films and liquid crystals [J]. Opt. Phys. Mater., 1996,5(2):165-187.[6] Lutfar R, Sandeep K, Carsten T, et al. Synthesis and photoswitching properties of bent-shaped liquid crystals containing azobenzene monomers[J]. Liq. Cryst., 2009,36(4):397-407.[7] Liu Z F, Hashimoto K,Fujishima A. Photoelectro chemical information storage using an azobenzene derivative [J]. Nature, 1990, 347:658-660.[8] Ikeda T, Tsutsumi O. Optical switching and image storage by means of azobenzene liquid-crystal film [J]. Science, 1995,268(5219):1873-1875.[9] 李增俊,沈冬.含偶氮基团的不对称弯曲型液晶分子的合成及光谱特性研究 [J]. 液晶与显示, 2011, 26(3):274-280.[10] Cheung D L, Clark S J ,Wilson M R. Calculation of the rotational viscosity of a nematic liquid crystal [J]. Chem. Phys. Lett., 2002, 356(1-2):140-146.