The experimental concentration dependences of oxide (BeO, MgO, ZnO) melts are described by the equations of polymeric model. The values of polymerization constants in the systems of MnO-TiO2, FeO-TiO2, CaO-TiO2 and MgO-TiO2 are evaluated by using these equations. They also are applied to calculate the activity of oxides in silicate melts, containing TiO2. Variation of titanium coordination by oxygen from 6 to 4 with the rise of TiO2 concentration is studied.