3. Concentrations of Sn²⁺ and Sn⁴⁺ Estimated for the 1-9SnNd Glasses Based on Mössbauer Spectroscopy Analysis (Table ) and the Nominal Concentrations of SnO (Table ).

glass	Sn2+ (mol %)	Sn4+ (mol %)
1SnNd	0.78	0.22
3SnNd	2.47	0.53
5SnNd	3.91	1.09
7SnNd	5.73	1.27
9SnNd	7.70	1.31