Absorption, luminescence, resonance Raman, and resonance CARS spectroscopy on FBS diacetylene single crystals with color zones

Abstract

Color zones in FBS (FPhSO 2 OCH 2 C≡C-C≡CCH 2 OSO 2 PhF) diacetylene single crystals are investigated by means of various optical spectroscopical methods in order to derive a plausible model for the origin of this type of chromism. Absorption, luminescence, resonance Raman, and CARS spectroscopy revealed that most probably growth defects in {111} crystal growth sectors influence the side group geometry of FBS polymer chains. This results in shortening of the π-electron conjugation lengths and in consequence in an anti-Stokes shift of electronic and vibrational transition frequencies