The gelation during free-radical crosslinking copolymerization (FCC) of methyl methacrylate (MMA) and ethylene glycol dimethacrylate (EGDM) was studied by using fast transient fluorescence (FTRF) technique. Pyrene (Py) was used as a probe for the FTRF experiments. Fluorescence lifetimes of Py from its decay traces were measured and used to monitor the gelation process at various temperatures. MMA consumption rates were measured during gelation process by using the Stern-Volmer model. Gelation activation energy DeltaE(G) was measured and found to be 15.6 kcal mol(-1). (C) 2001 John Wiley & Sons, Inc.