The designing of new glasses has proven to be a very challenging task due to the various complications and impacts every chemical element in use has on the resulting glass. During this master thesis the impact of the network modifier (NWM) barium on an aluminoborosilicate (ABS) glass has been analysed. To gain a better understanding of how the ratio of [NWM]/[Al_2 O_3 ] influences physical and mechanical properties, four different Ba-ABS glass compositions were created. While the content of barium differed for every composition, the [SiO_2 ]/[B_2 O_3 ] ratio as well as the portion of [Al_2 O_3 ] stayed constant throughout the series. It has been found that hardness, density and various elastic moduli (Young¿s, shear and bulk) rose with increasing barium content, whereas properties such as crack resistance and indentation fracture resistance decreased. A probable explanation for this behaviour could be the transformation of three coordinated, trigonal boron (B^III ) into four coordinated, tetrahedral boron (B^IV ) due to local charge stabilization. Other properties like brittleness and fracture toughness did not show any correlation with the amount of barium in the glasses. The results of this analysis deepen the understanding of how the amount of NWM influences the physical and mechanical properties of ABS glasses and therefore help to further tailor ABS glasses to specific applications.