INFLUENCE OF ALUMINA-CONTENT AND MODIFIERS ON PHASE-SEPARATION IN SODA-LIME-SILICA GLASS

The phase separation behaviour of industrial soda-lime-silica glass is studied by visible light scattering. The main aspects which different iate industrial glass from the ternary glass (composition in wt%): 76 SiO2, 13 Na2O, 11 CaO are considered. The obtained results show that t he simple ternary glass easily develops phase separation upon annealin g at suitable temperature levels. Conversely, container glass is stabi lized against demixtion by the presence of a significant Al2O3 concent ration, a significantly lower SiO2 content and a more complex chemical formulation (partial substitution of SiO2, Na2O and CaO with Al2O3, K 2O and MgO, respectively, as well as minor ingredients).