Sodium borotellurite glasses in the system xNaF₂-(20-x) Na₂O-40B₂O₃-40TeO₂ (0 < x < 20 mol%)  were prepared by  melt quenching method. The density related parameters such as molar volume elastic constants and thermal properties were studied for present glasses with increasing NaF₂ concentration. The results show that the calculated parameters strongly depend on increasing NaF₂ concentration.  The density reduction is  due  fluorine ions will enters interstitial spaces of the network and breaking B-O-Te bonds which results decreasing density of the present glasses. The elastic constants of the present glasses were found to decrease with NaF₂ content. This results in an increase of the discontinuity of the glass network. The thermodynamically parameters such as glass transition temperature and onset of crystallization temperature of the present glasses and were found to decrease as a function of NaF₂ concentration.