端基含己氧基偶氮苯基元的一代光致变色液晶碳硅烷树状物的光响应行为研究

Photoresponse Behaviour of a New Photochromic Liquid Crystalline Carbosilane Dendrimer of the First Generation Containing Hexyloxyazobenzene Moieties Groups in Its Periphery

研究了端基含己氧基偶氮苯基元新的一代碳硅烷光致变色液晶树状物 G1及其偶氮基元化合物 M3在各种溶液中的反顺光异构化反应速率常数、光回复异构化反应速率常数、热回复异构化反应速率常数、量子产率、活化能和异构转换率 .G1和 M3的光致变色速率常数为 0 .1 s- 1 ,比对应的光致变色液晶聚硅氧烷的光响应速度快 1 0

Studies were made of on the absorbance at 360 nm A 360, difference of absorbance at 360 nm ΔA 360, intensity of light I 0, absorption intensity of light I a, molar extinction coefficient at 360 nm ε 360, maximum absorption wavelength λ max, quantum yield Φ, activation energy E, trans/cis isomer absorbance ratio A/A 0, trans/cis photo-isomerization reaction rate constant k p, photo back-isomerization positive/counter reaction rate constants k t and k c, thermal back-isomerization reaction rate constant k H at different temperatures and photo back-isomerization reaction equilibrium value k t/k c of a new carbosilane photochromic liquid crystalline(LC) dendrimer of the first generation(G1) containing twelve 4-hexyloxyazobenzene moieties in its periphery and azobenzene unit M3 in solvents such as chloroform, tetrahydrofuran and so on. solvent were described. The photochromic rate constant of G1 and M3 are 10 -1 s -1, their photoresponsive rate are 10 7 times larger than that of photochromic liquid crystalline polysiloxane.