端基含4个丁氧基偶氮苯介晶基元光致变色液晶树状物的光化学研究

研究了新化合物含4个丁氧基偶氮苯介晶基元的零代(D0)光致变色液晶树状物在氯仿和四氢呋喃中的吸收光强、最大吸收波长、摩尔消光系数、量子产率、活化能、异构转换率、反-顺光异构化反应速率常数、热回复异构化反应速率常数、光回复异构化反应平衡常数及速率常数．D0的光致变色反应速率常数为10^-1s^-1，而含偶氮基元液晶聚硅氧烷的光致变色反应速率常数为10^-8s^-1，因此液晶树状物D0的光响应速度比后者快10^7倍．

Study on Photochemistry of Photochromic Liquid Crystalline Dendrimer Containing Four 4-Butoxyazobenzene Mesogenic Groups in Its Periphery

The photochemical behavior of a new photochromic liquid crystalline (LC) carbosilane dendrimer of the zero generation (D0) in CHCl 3 and THF was described. Four 4-butoxyazobenzene mesogenic fragments were attached in its periphery. The intensity of light absorbed, molar extinction coefficient, maximum absorption wave length, quantum yield and activation energy were determined. The reaction rate constants of trans/cis photochemical isomerization, photochemical back-isomerization and thermal back-isomerization and the equilibrium constant of photochemical back-isomerization reaction were discussed. Photochromic reaction rate constant of D0 is 10 -1 s -1, but that of photochromic LC polysiloxanes containing azobenzene moieties is 10 -8 s -1, thus the photoresponsive rate of LC dendrimer D0 is 107 times larger than that of the latter.