Effect of adding iron oxide (Fe2O3) in the sodium borate glasses (B2O3-Na2O) in the structural and physical properties was studied. Samples of the studied glass system were prepared with different percent of Fe2O3 concentration. This latter was added by substitution of the B2O3 and Na2O at concentration of (05, 10, 15 and 20 by wt %). The structural and physical properties of obtained glass were evaluated. The measurements of physical properties show that, in term of the glass density is relatively high with also high thermal expansion coefficient values with Fe2O3 presence. In the studied glass system, addition of transition iron oxide (Fe2O3) leads to weakened structure of glass so the transition temperature (Tg) and the softening temperature (Ts) decrease with increasing of Fe2O3 addition.