The UV stability of liquid crystal compounds containing tolane group was studied.It showed that the threshold voltage and birefringence of the liquid crystal decreased after 200 minutes of UV exposure. And it indicated that UV degradation of the liquid crystal depended on not only the absorption wavelength but also the detailed molecular constituents.The UV stability of liquid crystal with different terminal groups and linking groups were analyzed.The measured data showed that the diphenyl acetylene compounds with NCS terminal group exhibited a better UV stability than those with CN terminal group.The compounds with 1
4-cyclohexyl linking group were better than those with -COO- linking group or with none linking group.
关键词
Keywords
references
Greubel W, Wolff U, Kruger H.Electic field induced texture changes in certain nematic/cholesteric liquid crystal mixtures [J].Mol.Cryst.Liq.Cryst., 1973, 24(1-2): 103-111.[2] Doane J W, Vaz N A, Wu B G, et al. Field controlled light scattering from nematic microdroplets [J].Appl.Phys.Lett., 1986, 48(4): 269-271.[3] Yang D K, West J L, Chien L C, et al. Control of reflectivity and bistability in displays using cholesteric liquid crystals [J].J.Appl.Phys., 1994, 76(2): 1331-1333.[4] 贵丽红,丰景义,史子谦,等. 向列相液晶旋转黏度测试方法的研究 [J]. 液晶与显示, 2013,28(4): 527-533. Gui L H, Feng J Y, Shi Z Q, et al. Method of measuring nematic LC rotational viscosity [J].Chinese Journal of Liquid Crystals and Displays,2013, 28(4): 527-533.(in Chinese)[5] Tarumi K, Finkenzeller U, Schuler B.Dynamic behavior of twisted nematic liquid crystals [J].Jpn.J.Appl.Phys., 1992, 31(1): 2829-2836.[6] Gooch C H, Tarry H A.The optical properties of twisted nematic liquid crystal structures with twist angles≤90 degrees [J].J.Phys.D: Appl.Phys., 1975, 8(13): 1575-1584.[7] Wu S T, Efron U, Hess L V.Infrared birefringence of liquid crystals [J].Appl.Phys.Lett., 1984, 44(11):1033-1035.[8] 史子谦,丰景义,贵丽红,等. 高折射率液晶化合物与液晶混合物 [J]. 液晶与显示, 2013,28(3): 310-314. Shi Z Q,Feng J Y, Gui L H, et al. High birefringence LC compounds and LC mixtures [J].Chinese Journal of Liquid Crystals and Displays, 2013, 28(3): 310-314.(in Chinese)[9] Wu S T, Ramos E.Polarized UV spectroscopy of conjugated liquid crystals [J].J.Appl.Phys.,1990, 68(1):78-85.