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

Abstract 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.