Solutions of salts in amorphous polyethers and charged species derivatized with polyethers have been found to both adhere to a common plot of glass transition temperature, T-G, against cationic charge per polyether oxygen. It is proposed that the T-G increase is mainly due to the (ion-dipole) solvation of cations, which increases the barriers to segmental motions. The salt induced shrinkage of the polymer only partially contributes to the increase and coordinative crosslinking by the cations has been ruled out as a principal cause.