Analysis of UV-Vis spectral profiles of solvatochromic poly[3-(10-hydroxydecyl)-2,5-thienylene]

The paper discusses a systematic study of the UV-Vis spectral profiles of poly[3-(10-hydroxydecyl)-2,5-thienylene] during its solvatochromic transformation in different solvent/non-solvent mixtures. A simulation of the overlapped spectra of the two chromophores (A less and B more conjugated) of the polymer is made through the resolution of their pure forms by means of vibronic progressions of log_normal curves. The increment of the absolute intensity observed in the transformation has been determined and related to the increment of the transition moment; its value strongly supports the hypothesis that the solvatochromic transition consists in a doubling of A chromophores. Estimation of the average length of B chromophores has made it possible to evaluate the oscillator strength in the different solvent mixtures, the Franck-Condon factor and the Huang-Rhys parameter in relation to the intensity distribution of the vibronic structure. (C) 2002 Elsevier Science B.V. All rights reserved.