New Phosphorescence Probes for Monitoring the Kinetics of Thermal and Photochemical Polymerization

Abstract

Several organometallic complexes have recently been demonstrated to act as spectroscopic probes of kinetic changes taking place on polymer network formation. This review summarizes the recent development of these phosphorescence probe molecules in both thermal polymerization and photo-initiated processes. Polymers based on epoxy and aromatic cyanate ester thermosetting materials and epoxy and acrylate photosensitive resins are discussed. Most attention is focused on fac-ClRe(CO)₃(where 4,7-Ph₂-phen) (4,7-Ph₂-phen = 4,7-diphenyl-1,10-phenanthroline), and on closely related complexes, as they are strongly luminescent in the visible region and appear to offer considerable promise in probe applications. These spectroscopic probes are shown to be sensitive to viscosity changes of over five orders of magnitude within the polymer network. The luminescence features of these organometallic probe complexes are compared to that of other organic probe molecules.