Aniline and methyl, ethyl, propyl, and methoxy ring substituted derivatives have been polymerized by electrochemical methods. The reduction of the film produces aging of the polymers. This is followed by the changes in the current/potential profile of the voltammetric response. The effect of the substituents produces changes in both the extent and the rate of aging. The rate of aging can be represented by a Roginsky-Zeldovich or Elovich type of kinetics characterized by a pseudo zero order rate constant and a self-inhibiting parameter. Both parameters and the extent of aging are related to the free volume available for the different types of polymers.