Investigation of the Structure and Properties of Glasses in the System La2O3–MnOm–B2O3 (M = Nb, Ta, Ti, Zr)

The results of the synthesis of lanthanum borate glasses modified with highly polarizable cations (Nb, Ti, Zr, Ta) are described, their crystallization properties were studied, and their structural features were investigated by means of IR spectroscopy. It was determined that glass blanks with refractive index > 1.8 can be obtained in the composition range 25La2O3–xMnOm–(75 – x )B2O3 (M = Nb, Ta, Ti, Zr, x = 5 – 25 mol.%). It is proposed that a network of large polyhedra of the modifying cation, which are bound at the vertices, is formed in addition to the borate network, thereby allowing the melt to retain its glass-forming ability.