SPECTROSCOPIC PROPERTIES OF 3-(2-BENZOTHIAZOLYL)-7-OCTADECYLOXY COUMARIN IN LANGMUIR-BLODGETT-FILMS

The spectroscopic properties of 3-(2-benzothiazolyl)-7-octadecyloxy co umarin (BOG) in solution and in Langmuir-Blodgett (LB) films at room t emperature and at 77 K have been investigated, Amphiphilic BOC forms e xcellent LB films which show intense fluorescence at room temperature. At 77 K the films also exhibit phosphorescence and delayed fluorescen ce of triplet-triplet annihilative origin. Spectroscopic studies revea l that at room temperature dimers or low-order aggregates are formed. Lowering of the temperature results in the formation of higher aggrega tes or microcrystallites. Fluorescence lifetime studies confirm such a ggregation of BOC in LB film.