A Raman-spectroscopic study of indentation-induced structural changes in technical alkali-borosilicate glasses with varying silicate network connectivity

Plasticity, crack initiation and defect resistance in alkali-borosilicate glasses: From normal to anomalous behavior

“…To ensure homogenous melts, the glasses with SiO 2 contents higher than 70 mol% were quenched in water and re-melted after drying. All melts were poured into preheated graphite molds (~20-50 K above the glass transition temperature) and cooled down to room temperature at a rate of 30 K/h, except for the Duran-type composition, which was cooled in the crucible, and the model glasses NBS A, C and D, which were quenched down to room temperature [33,34]. For comparison, commercially available SiO 2 (Suprasil, Heraeus Quarzglas GmbH & Co. KG) was analyzed as well.…”

“…Data on T g and ρ are taken from Refs. [33][34][35] echoes. The shear modulus G, bulk modulus K and elastic modulus E as well as the Poisson ratio ν were calculated using the following relations, which are applicable for isotropic materials [39]:…”

“…However, higher modifier oxide concentrations (R N 0.5) cause NBO to form on trigonal borate groups, and/or on silicate tetrahedra. This coordination change makes borate containing glass systems very interesting for studying the material's response to indentation deformation, as the network can be manipulated with respect to the degree of polymerization, not only considering the number of non-bridging oxygen ions, but also considering the BO 3 /BO 4 ratio [32][33][34].…”

“…In the present study, we provide systematic data on the elastic properties, Poisson ratio, hardness, the relation between densification and volume conservative shear flow, and correlations to damage tolerance for a range of compositions of the well investigated alkaliborosilicate system [11,12,34]. We focus on variations of the R-and K-values, i.e., BO 3 /BO 4 ratios and also varying amounts of NBO, within the technologically most relevant part of the ternary (which also contains the regions of immiscibility).…”

Composition dependence of crack formation probability in aluminoborosilicate glass

“…Winterstein-Beckmann et al conducted a Raman spectroscopic study in alkaliborosilicate glass and reported that indentationinduced structural changes depend on not only borate concentration but also silicate sub-network connectivity [15]. They also reported that the largest value of CR is not obtained for the composition that shows the highest values of densification to total indentation volume ratio.…”