The viscosity behavior of various compositions of polymer electrolyte membrane solutions, which are later hydrolyzed into proton conducting membrane film for fuel cells, is characterized. Using the Carreau-Yasuda model and time-temperature superposition, an empirical model relating the viscosity as a function of temperature and shear strain rate has been developed for several membrane solution compositions. It is observed that the viscosity of the non-Newtonian membrane has a strong correlation to the membrane's inherent viscosity (a property determined during membrane synthesis). (c) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 111: 1286-1292, 2009