A relationship between dynamic storage modulus (E′) and the mean cross-polarization time constants 〈TCH〉 for 16 polymer data sets has been established by using a standard linear solid model. This model is used in an attempt to equate the process of cross-polarization with mechanical rigidity by virtue of the implicit dependence of each phenomenon on molecular motion. The apparent validity of the relationship between these parameters indicates that cross-polarization in polymers can be a function of molecular motion in addition to microscopic spin dynamics. The limitations as well as practical applications of this relationship are discussed. © 1993 John Wiley & Sons, Inc.