Glasses with the compositions (23.1-x)Na 2 O/23.1BaO/23TiO 2 /9.8B 2 O 3 /21SiO 2 /xAl 2 O 3 x = 3, 7, 11 and 15 mol% were melted using a traditional melt-quenching technique. The thermophysical properties of the obtained glasses, i.e., glass transition temperature, T g , and crystallization peak maximum temperature, T c , were determined by differential scanning calorimetry and showed that the increasing alumina concentration leads to an increase of both the T g and T c values, while the difference T g -T c , used as a glass stability criterium, changes in the opposite manner, being highest for the glass with 3 mol % Al 2 O 3 and smallest for the composition with 15 mol % Al 2 O 3 . The structure of the prepared series of glasses was studied by infrared spectroscopy and showed that the main structural units present are isolated and interconnected SiO 4 tetrahedra. Both BO 4 and BO 3 structural units, which number initially increases with the increasing alumina concentration and then starts to decrease, are also present. The conducted depth-sensing indentation on the obtained glasses allowed to determine mechanical properties such as universal (HMV) and indentation (Hit) hardness, elastic modulus and elastic part of indentation work. The change of the Na 2 O/Al 2 O 3 ratio resulted in increasing HMV and H it up to 11 mol% Al 2 O 3 and then a slight decrease of the respective parameters was observed.