Rheological measurements and results discussed in this paper made on gelling mass containing thetraethoxysilane (TEOS or Si(OC2H5)(4)) and calcium nitrate as sol-gel precursors is important because of the interest of sol-gel processes as a possible preparation route of glasses and amorphous body structures (sol-gel route). The rheological measurements in our study, have been made to investigate the set-gel transition of Si(OC2H5)4 by measuring the viscosity evolution at time intervals and temperature values established. The temperature dependence of the viscosity was used to determine the activation energies of the flow.