The effect of hydrogen bonding on the phase behavior of binary polymer blends of poly(ethylene covinyl alcohol) (EVOH) with poly(n-butyl methacrylate) (PBMA) and poly(4-vinyl pyridine) (PVPy) was studied by Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR/ATR). The association model of Painter, Coleman, and co-workers was used to analyze the effect of hydrogen bonding on miscibility of polymer blends containing EVOH. The equilibrium constants of solvation of EVOH with PVPy are determined from the quantitative analysis of spectra at 60, 100, and 140 degreesC and compared with previous results available at room temperature. The equilibrium constants of solvation of EVOH with PBMA were similarly determined at 60, 100, and 140 degreesC. Results for these binary blends are of interest in understanding the roles of compatibilizers and predicting results for multicomponent blend. Because the pyridine nitrogen and the carbonyl oxygen absorb in different regions of the IR spectrum, this choice of components provides a useful combination for probing the role of hydrogen bonding.