Structural Insights into the Enhanced Crystallization Resistance of B2O3-Modified Aluminophosphate Glasses

The structural evolution of the glasses was analyzed by a multi-scale characterization approach including Raman spectroscopy, multinuclear solid-state NMR (11B, 27Al, 31P) with advanced dipolar recoupling experiments (31P{27Al}, 27Al{31P}, 11B{31P}, and 31P{¹¹B} REDOR), as well as neutron and X-ray total scattering with pair distribution function analysis.

The thermal, physical, and chemical properties of the glasses were systematically measured. With increasing B2O3 content, it is found that B2O3 is incorporated exclusively as tetrahedral [BO4] species forming P–O–B cross-links while preserving P–O–Al connectivity, preferentially substituting P–O–P bridges within Q2 phosphate chains with P–O–B linkages and promoting Al coordination redistribution from Al(VI) toward Al(V) and Al(IV).