ESR analysis of the initial reaction products in the solid state photopolymerization of diacetylenes

In order to investigate the mechanism of the solid state photopolymerization of single crystals of the bis(p-toluene sulphonate) ester of 2,4-hexadiyne-1,6 diol (TSHD) the low temperature UV-photoproducts are analyzed by ESR-spectroscopy. In this paper we report the fine structure, hyperfine structure and temperature dependence of a series of thermally activated triplet diradicals. The structure of these diradical dimer and trimer initiators of the UV-photopolymerization process is deduced from the analysis of the ESR data.