Abstract: ¹¹B NMR studies have been carried out in the system of lithium borosilic-ate glasses Li₂O-B₂O₃-SiO₂ The fraction of BO₄ and BO₃ units was measured and analyzed according to a structural model.The results indicate that the ternary system can be explained by a modified FDB model. The difference between the binary and ternary system is the sharing of Li₂O between borate and silica.