A method which utilizes experimental measurement and modeling of photoacid-catalyzed deprotection rates obtained via Fourier transform infrared spectroscopy has been developed for determining photoacid generator (PAG) photoreaction rate constants (i.e., Dill C parameters) in protected polymer matrices. Numerical modeling of deprotection rates as a function of exposure dose and postexposure bake time is used to determine the Dill C parameters for the PAG in the actual resist matrix polymer of interest. This protocol is shown to be a fast, nondestructive, and material-saving technique that can permit measurement of Dill C parameters in reactive polymer matrixes. (c) 2007 The Electrochemical Society.