Photopolymerization of Diacetylene Crystals: Reaction Kinetics and Holography

Abstract

The intermediate products during the solid state photopolymerization of TS (2,4-hexadiynylenebis-(p-toluene-sulfonate)) are investigated by time resolved optical absorption spectroscopy. The absorption transients after the initiating UV laser flash unambiguously confirm the most simple kinetic model: the intermediate products are short oligomers which react in a direct sequence. The fit between the calculated and the experimental optical transients is almost perfect. The temperature dependencies of the rate constants yield activation energies ΔE (0.25 eV ≤ ΔE ≤ 0.30 eV) and frequency factors (10¹¹ s⁻¹) which give a hint to the vibration which is driving the reaction.

Holographic gratings on the surface of TS-crystals, generated by coherent UV-light, show TS to be a photographic material with high spatial resolution which needs no developing process.