A method has been developed which permits a complete molecular structure description of a polymeric material. Very good molecular descriptions have been achieved for certain epoxy-novolac resin-alicyclic anhydride polymers, which were catalyzed by tertiary amine, by using refined analytical techniques and computer correlation of the analytical data. The method and results are described. The chemical compositions of cured polymers containing various ratios of epoxy-novolac to anhydride are illustrated. The information generated by this work (Contract NAS 7–344) was one element of the NASA-Ames Research Center program to improve char-forming heat shield polymers.