Optical properties of bis(p-toluene sulphonate)diacetylene. I. Crystal optics of partially and fully polymerized crystals

Abstract

The solid state polymerization of bis(p-toluene sulphonate)diacetylene proceeds via a single-phase solid solution. The optical constants of the pleochroic partially polymerized crystals are determined. Spurious “absorption lines”, due to an intense Brewster's brush, are observed, especially when increasing polymer content leads to pronounced dispersion of the optic axes. The optical constants of fully polymerized crystals for light polarized parallel to the conjugated polymer chains are calculated from the reflection spectra. These data enables the principal values of the absorption ellipsoid of the chains to be determined and compared with theoretical predictions.