The crosslinking of functionalized polystyrene resins is often of critical importance in determining resin properties and performance in the application of these materials as membranes and supports. In this investigation model systems are developed for quantifying the infrared and Raman spectroscopic properties of copolymers based on poly(styrene-co-divinylbenzene). Analytical curves appropriate for the quantification of para- and metasubstituted species and pendant double bonds are reported, and corrections to previously reported spectroscopic assignments and analytical methods are made. The usefulness of these two analytical methods in characterizing radiation-grafted films and commercial copolymers is compared, and typical characterization results are given. The relative concentrations of the species found in the grafted films are quite different from their concentrations in the grafting solution, and empirical relationships between the two are developed. In addition, the graft composition varies as a function of the base polymer film thickness and type and the penetration depth in the grafted film. Radiation-grafted films are more highly crosslinked in their near surface regions, and thinner films are more extensively crosslinked. (C) 2003 Wiley Periodicals, Inc.