共轭双键结构不同的三种有机染料分子的拉曼光谱研究

Raman Spectroscopy studies of Three Organic Dyes with Different Conjugated－bond Structures

共轭双键结构不同的三种有机染料分子的拉曼光谱研究姚文华（复旦大学分析测试中心上海２００４３３）马世红，刘丽英，王文澄（三束材料改性国家重点实验室，复旦大学物理系上海２００４３３）ＲａｍａｎＳｐｅｃｔｒｏｓｃｏｐｙｓｔｕｄｉｅｓｏｆＴｈｒｅｅＯｒｇａｎ...

Abstract Three organic dyes，diazostilbenes （ HPNA ）， phenylhydrazone（PD）and hemicyanine （DAEP），all have large hyperpolarizability but differ-ent double bonds in their conjugated electron systems （N= Nin HPNA，C= N in PD and C＝Cin DAFP）． We investigated the stability of Z－type LB multi-layers of the 3 dyes and found that the SHG intensity from those samples re-duced significantly within a few tens of days. On the other hand， the Raman spectroscopy intensities due to the vibrational modes of the double bonds from the powders of the 3 dyes also decreased with increasing time of irradiation by amercury lamp，confirming the breakdown of the double bonds in all the 3 dyes （photo bleachingn）．Both SHG and Raman spectroscopy experiments de-duced the same sequeiice of stability： N＝Nthe worstand C＝Cthe best sug gesting that photo bleaching effect， instead of deterioration in molecular ar－rangement， could possibly be responsibie for the instability of opticaｌ nonlinear LB films.