Spectroscopic Analysis of the Structure of Silicate Glasses along the Joint x MAlO 2 ‐(1– x )SiO 2 (M = Li, Na, K, Rb, Cs)

Infrared spectroscopic studies of charge‐coupled substitution in silicate glasses and crystals along the joints x MAlO 2 (1 – x )SiO 2 (M = Li, Na, K, Rb, and Cs; 0.10 ≤ x ≤ 0.60) were carried out in the range 2000 to 200 cm −1 Three major absorption bands appeared in the 1100‐, 800‐, and 500‐cm −1 regions. For a specific value of x, the observed changes in frequency, intensity, and bandwidth decreased in the order Li > Na > K > Rb > Cs and the apparent disorder in the glass structure caused by the substituted aluminum increased in the direction K < Na < Li. The 800‐cm −1 band splits at SiO 2 ≃ 0.75 mol, which has been interpreted in terms of the number of AlO 4 tetrahedra in the structure. Most of the substituted aluminum in the glasses and the crystals was found to be in the fourfold coordination.