THERMOCHROMISM OF ALKYL SUBSTITUTED POLY(DITHIOPHENEDIYLVINYLENES)

A spectroscopical study of the thermochromic effect of butyl and octyl substituted poly[ (2, 2?-dithiophene)-5,5?-diylvinylene] films (herein 4PDTV and 8PDTV) is reported. The optical absorption spectra shift to higher energies by increasing the temperature. These reversible changes have been monitored by IR absorption and Raman scattering. The measurements do not show a relevant backbone distortion upon heating. This seems an indication that these polymers are more rigid than poly-3-alkylthiophenes.