2004 Volume 44 Issue 1 Pages 43-49
For the molten Na2O-SiO2-Al2O3 system, the distributions of Al3+ ions in the various complex anions and the interconnected relations between the Si tetrahedra and Al tetrahedra consisted of the complex anions have been studied by molecular dynamics simulation and Raman spectroscopy. From the interconnected relations between Si and Al tetrahedra calculated by the molecular dynamics simulation, the abundance of complex anions was evaluated. Based on the abundance of these anions, the degree of polymerization in Na2O-SiO2-Al2O3 melts was found to be enhanced by the substitution of Al2O3 for SiO2. The Raman spectroscopic band at around 520 cm−1 related to the three-dimensional network structure was found to develop with the replacement of SiO2 by Al2O3 under the constant Na2O content. Based on these results by molecular dynamics simulation and Raman spectroscopic measurements, it was confirmed that the Al3+ ion had a strong preference to enter the three-dimensional network structure.