Annealing effects in SiO2-Na2O glasses investigated by Brillouin scattering

The elastic energy due to residual stresses in non-annealed SiO2-Na2O glass es. is determined in the frame of the theory of elasticity, assuming that a non-annealed glass can be considered as a distorted material in comparison with the annealed glass. An analysis of the elastic energy which is releas ed at annealing is presented. Using hypotheses concerning the localisation of this energy in the glass and structural relaxation at annealing has allo wed us to recalculate values of cation vibrational mode frequencies measure d by infrared spectroscopy. The annealing effects on mechanical properties are,studied and analysed in terms of glass structure, including phase separ ation at low sodium concentration. (C) 2001 Published by Elsevier Science B .V.