Abstract Differential scanning calorimetry (DSC) has been used to investigate the thermal transitions occurring for a series of eight Argonne Premium coals. Each of the coals was subjected to different heating/cooling profiles in order to determine the effect of cooling at varying rates on the second order process and to determine the effect of temperature of exposure on the second order process. The variable cooling rate scans showed that the position of the transition increased with decreasing cooling rate of the previous scan. The sequential heating scans demonstrated that the rank of coal had a direct influence on the resistance of the second order process to exposure to heat. Low rank coals showed a greater degree of resistance and this was assumed to be related to the density of non-covalent bonds within the structure.