In situ, real-time steady state fluorescence measurements used for studying the dissolution of polymer films. These films were formed from pyrene labelled poly(methyl methacrylate) (PMMA) latex particles, sterically stabilized by polyisobutylene. Annealing was performed above the T-g at 180 degrees C during Ih for film formation. Desorption of pyrene labelled PMMA chains was monitored in real time by the change in pyrene fluorescence intensity. Dissolution experiments were performed in toluene and a toluene/heptane mixture at elevated temperatures. Relaxation (k(0)) and diffusion (D) parameters were measured and found to be around 10(-2) mg cm(-2) min(-1) and 10(-11) cm(2) s(-1), respectively. Using these parameters, relaxation (Delta E-ko) and diffusion (Delta E-D) activation energies were calculated and found to be 11.36 and 24.38 kcal mol(-1) and were attributed to the side-chain and backbone motions, respectively.