Styryl substituted terthiophene species have been used to
produce neutral polythiophene species which show distinct Raman
frequency dispersion. The polythiophene line B band shows dispersion values
of: –0.12, –0.07, –0.1 cm–1 nm–1 for the phenyl, para-methoxy phenyl and
para-cyano phenyl systems respectively. This is smaller than the dispersion
values reported for polythiophene presumably because the intramolecular
stacking forces that oppose the normal dispersion effect are suppressed due
to the substituents we have used.