Anaerobic adhesives cured by a redox initiated free radical mechanism contain acrylate monomers, stabilizers, accelerators, a nonreactive fluorophore used as an inspection aid, and various nonreactive ingredients to modify polymer properties and rheology. Fluorescence spectroscopy has shown that collisional quenching of the fluorophore due to an an-Line cure-accelerator is reduced by rising viscosity during polymerization, thus resulting in an increase in fluorescence intensity. By monitoring the changes in fluorescence intensity with an in situ fiber-optic method, room temperature polymerizations have been characterized both in a model formulation containing only reactive ingredients as well as in a real commercial formulation containing many nonreactive ingredients. The results from this fluorescence method on polymerization monitoring show excellent correlation with the FTIR results. (C) 2007 Wiley Periodicals, Inc.