In situ steady-state fluorescence (SSF) measurements were used for studying dissolution of Latex films in real time. Latex films with various thicknesses are formed from pyrene (P) labeled poly(methyl methacrylate) (PMMA) latex particles, sterically stabilized by polyisobutylene (PIB). Annealing of latex films were performed above T-g at 220 degrees C temperature for 60 min. UV-Visible (UVV) spectrometer was used to measure the transparency of latex films. It was observed that thicker films formed more opaque films than thinner films. Heptane (20%), chloroform (80%) mixture was used as a dissolution agent. Diffusion of pyrene labeled PMMA chains was monitored in real time by the change of pyrene fluorescence intensity, I-P in the polymer-solvent mixture. Diffusion coefficients, D, and relaxation constants, k(0), of PMMA chains were measured and found to be strongly dependent on the latex films thicknesses. It is observed that thicker and opaque films dissolved much faster than the thinner and transparent films.