The present research addresses the investigation of the mechanical and viscoelastic properties of films consisting of sodium alginate cross-linked with divalent Ca 2+ and Ba 2+ ions. Fourier-transform infrared and Raman spectroscopy techniques confirmed the development of the Ca- or Ba-alginate structures. Both techniques revealed a shift of the COO vibration modes; The Raman mode assigned to the symmetric carboxylate stretching vibration was slightly shifted from approximately 1593 cm -1 to 1597 cm -1 or 1603 cm -1 in the spectra of Ca- and Ba-alginate films, respectively. TMA analyses performed revealed that increasing the Ca and Ba molarity and immersion time resulted in an increase in the glass transition temperature (T g) and the strain of the Ca- and Ba-alginate films. This rising trend in T g was attributed to the less mobility of the molecular chains of polymer as well as the enhanced degree of cross linking by prolonging the curing time or increasing the divalent cation concentration.