Polymer was synthesized from the polymerization of 8-hydroxyquinoline 5-sulphonic acid and catechol with formaldehyde (8-HQ- 5- SACF) by solution condensation in an acid medium. The polymer was characterized by elemental analysis, UV-Visible spectra, FTIR and NMR spectroscopy The thermal stability of the polymer was determined by TGA. In addition, the activation energy for the formation of polymer was calculated using TGA data by Freeman-Carroll method and Sharp-Went-worth method. The surface features of the polymer was analyzed by scanning electron microscopy (SEM). The thermodynamic parameter such as free energy change (ΔF), entropy change (ΔS) , Apparent entropy change( S*) and frequency factor Z are also determined on the basis of TGA curve and by using data of Freeman-Carroll method .