The effect of oxide additions on medium-range order structures in borosilicate glasses

Abstract

Boron-11 nuclear magnetic resonance (MAS NMR) and Raman spectroscopies have been used to study four families of glasses: xCs₂O(100-x)ZMW (0<x<10), where ZMW represents the borosilicate glass MW to which oxides Z (Al₂O₃, La₂O₃ and MgO) are added such that, overall, 1.0≤R (= [modifier]/[B₂O₃])≤2.5; K (= [SiO₂]/[B₂O₃]) = 3.2. These glasses are related to the system used for the vitrification of high-level nuclear waste. The spectra reveal the presence of reedmergnerite and danburite medium-range order structural units in the glasses. The fraction of danburite units increases with the addition of caesium oxide when Al₂O₃ or La₂O₃ are present, and decreases when MgO is present.