Structural evolution at short and medium range distances during crystallization of a P 2 O 5 ‐Li 2 O‐Al 2 O 3 ‐SiO 2 glass

Abstract Li 2 O‐Al 2 O 3 ‐SiO 2 (LAS) glass‐ceramics have important industrial applications and bulk nucleation is usually achieved by using nucleating agents. In particular, P 2 O 5 is an efficient agent in glasses containing a low level of Al 2 O 3 but its role in the first stages of nucleation is not well established. In this study, we combine structural investigations from local to mesoscales to describe the structural evolution during crystallization of LAS glass‐ceramics. Local environment is probed using 29 Si and 31 P MAS‐NMR, indicating organization of P in poorly crystallized Li 3 PO 4 species prior to any crystallization. To better understand the detailed nanoscale changes of the glass structure, 31 P‐ 31 P DQ‐DRENAR homonuclear correlation experiments have been carried out, revealing the gradual segregation of P atoms associated with the formation of disordered Li 3 PO 4 . Small‐angle neutron scattering data also show the apparition of nanoscale heterogeneities associated with Li 3 PO 4 species upon heating treatments and allow the determination of their average sizes. These new structural information enhance our understanding of the role of P in nucleation mechanisms. Nucleation is initiated by gradual change in P environment implying P segregation upon heating treatments, forming disordered Li 3 PO 4 heterogeneities. The segregation of P atoms enables the precipitation of meta‐ and disilicate phases.