Nuclear magnetic resonance spectroscopy (NMR) gave information on the behavior of alpha-methylstyrene-co-acrylonitrile. The comonomer sequence distribution in the copolymer and the depolymerization process were detected by solution analysis. The solid-state NMR investigation showed that C-13 routine spectra such as MAS and CPMAS allowed one to obtain information on the molecular domains of chains and also permitted evaluation of the domains' mobility. In this case, the mobile domain was formed by alpha-methylstyrene (AMS). The variable contact time and the proton spin-lattice relaxation time in the rotating-frame parameter were determinant factors to evaluate the dynamic molecular behavior and the homogeneity of the comonomer distribution along the copolymer chains.