The structure of high-alkali Li20-B203 melts (> 50 mol. % Li20) have been studied by high-temperature Raman spectroscopy in the temperature range of 973-1373 K. Raman and IR spectra of polycrystalline samples have been measured also. With an increase in the Li20 content the B04 and B02O” metaborate units were converted into B0O2" pyroborate units and then in B033 orthoborate units. Concentration of these structural units depends on temperature. Reactions of interaction between structural units in melts are established.