Holographic recording in thiophene-based polyester

Abstract

The synthesis and optical data storage properties of a side-chain thiophene-phenyl azopolyester ThPhAzoPol is reported. The polyester is derived from diphenyl tetradecanedioate and a thiophene-based liquid crystalline diol which exhibits a short-lived enantiotropic SmA phase (Cryst 177.7 SmA 180.4 I). The polyester ThPhAzoPol exhibits amorphous (T_g, 78.6 °C), crystalline and liquid crystalline character as evidenced by differential scanning calorimetry and thermal polarising microscopy. A grainy texture, which is thermally reversible, with increasing birefringence on cooling from the isotropic melt is observed. The polyester is amenable to optical data storage, showing efficient induced anisotropy, which is stable at room temperature. Polarisation gratings can be inscribed using orthogonally linear and circularly polarised light to good effect (>1%) and surface relief gratings are formed in addition as evidenced by atomic force microscopy.