Bulk thermal polymerisation of diethylene glycol bis(allyl carbonate) as studied by dielectric relaxation spectroscopy

Broad-band dielectric relaxation spectroscopy (DRS) has been used to study the changes in molecular relaxation behaviour when diethylene glycol bis(allyl carbonate) (CR39 monomer) is polymerised thermally in its bulk state. As polymerisation proceeds the dielectric alpha-relaxation process broadens markedly and moves to higher temperatures while, at the same time, a small low-temperature beta-relaxation process increases in its intensity and moves to higher temperatures. The dielectric loss spectra are shown to provide a convenient fingerprint that indicates the extent of cure in partially cured materials.