Thermal degradation of poly(o-toluidine) (POT) reduced [base form (POT-EB)] and oxidized form [i.e. doped with salicylidine-aniline (SA) and/or salicylidine-o-aminophenol (SAP)] was investigated experimentally and computationally. The results of thermal (TGA) and differential thermal (DTG) gravimetric analysis suggest a higher thermal stability for the oxidized (SA or SAP-doped POT) than that for the respective reduced (POT-EB) chain. Nonisothermal degradation of the reduced POT matrix reveals hydrophilic nature about two times stronger than that for the oxidized form (SA and/or SAP-doped POT) under the same conditions. Molecular mechanics (MM
/) calculations substantiate these observations. FTIR spectroscopic study of the calcined POT-EB showed that the quinoid (Q) ring (iminostructure) is thermally at least twice more stable than for that the benzenoid (B) rings (aminostructure) in the repeating unit of the polymer chain. Isothermal degradation curves [fraction decomposed (a) vs. degradation time (t in min)] of the polymers under investigation revealed that they are characteristically declaratory in shape.