Applicability of decahydroacridine-1,8-dione derivatives as fluorescent probes for monitoring of polymerization processes

The behavior in polymerizable media of 3,3,6,6-tetramethyldecahydroacridine-1,8-diones substituted with aromatic rings at the 9- or 10-position has been studied. It has been found that the fluorescence of acridinediones shifts to shorter wavelengths upon polymerization of the medium, and this qualifies them as fluorescent molecular probes for monitoring the progress of polymerization processes. The shift in fluorescence is accompanied by a slow decomposition of the acridinediones to a fluorescent product under photopolymerization conditions, Acridinedione decay was slower than the polymerization of a typical photocurable formulation, thus allowing one to follow the progress of polymerization by fluorescence. The influence of the photoproduct on the monitoring of polymerization has been avoided by optimization of the monitoring parameters. Application of the acridinediones as fluorescent molecular probes for large scale applications in the coating industry is proposed. (C) 1997 Elsevier Science S.A.