Structural Particulars of Iron-Containing Borosilicate Glasses

The behavior of iron in the structure of sodium iron-containing borosilicate glasses with different ratio of the glass-forming and modifying ions was studied by Mössbauer and vibrational spectroscopy. It was found that the distribution of the modifying ions differs between different types of structural species in the structure of the initial and iron-containing sodium borosilicate glasses. The addition of iron decreases the BO4 tetrahedra fraction and increases the BO3 triangles fraction and the fraction of the structural species Q2 and Q3 containing nonbridging oxygen atoms. This is accompanied by the destruction of mixed silicon borate rings and the formation of the bridging bonds Si–O–Fe3+ and nonbridging bonds Si–O−, coordinated by Fe2+ ions.