Aging due to the storage time on latex film formation was studied using the photon transmission method. The UV visible technique was used to monitor the evolution of transparency during film formation from two different polystyrene (PS) particles produced by using two different steric stabilizers, i.e., polyvinyl alcohol and polyvinyl pyrrolidone. The latex films were prepared from PS particles at room temperature before and after aging and annealed at elevated temperatures in various time intervals above glass transition (T-g). The increase in the transmitted photon intensity I-tr was attributed to the increase in the number of disappeared particle-particle interfaces. Relative decrease in transparency and delay in film formation were observed in the aged latex films compared to the nonaged ones. The Prager-Tirrell model was employed to interpret the increase in crossing density at the junction surface. The back and forth activation energies (DeltaE) were measured and found to be dependent on aging for a diffusing polymer chain across the junction surface. (C) 2001 John Wiley & Sons, Inc.