Structure of Aluminoborosilicate Glasses: Role of Alkali Modifier

Oxide glasses are one of the most important material families, but their applications are severely restricted by the main drawback of glass, namely high brittleness. The relationship between glass structure and mechanical properties thus needs to be established. Aluminoborosilicate (AlBSi) glasses form the basis for a wide range of commercial glass products, but the role of alkali modifiers on their structure and mechanical properties is not well understood. Our aim with the current proposal is to collect neutron scattering data at the SANDALS diffractometer from AlBSi glass compositions with different alkali oxides (Li, Na, K). By doing so, we will obtain the neutron structure factor S(Q) to Q values >40 Å-1, enabling high-resolution computation of the pair distribution function and thereby allowing precise quantification of bond lengths and coordination numbers. In total, we will study 14 different glass samples with varying B/Al ratios and isotopic substitutions, requiring 4 days of beamtime. The neutron data will be combined with other structural characterization (solid state NMR and X-ray scattering) and modelling (molecular dynamics and EPSR) techniques to obtain a detailed understanding of the effect of the alkali modifier on the glass structure across different length scales. We will correlate the obtained structural models of AlBSi glasses with the glasses’ mechanical behaviour, which will ultimately aid the design of oxide glasses with improved damage resistance.