Structural study of rare earth doped fluoride phosphate glasses by solid-state nuclear magnetic resonance

A series of glasses with the compositions of 10NaF-(90-x) NaPO 3 -xYF 3 ( x  = 5, 10, 15 and 20 mol%) were prepared via the conventional melt-quenching method. The structures of these glasses were characterized by multiple advanced solid-state nuclear magnetic resonance (SSNMR) techniques. Multiple phosphorus species Q m nY were resolved at atomic level. Here, the value m and n denote the number of P–O–P bonds and the number of Y 3+ ion bounding to phosphorus oxygen tetrahedron, respectively, which were identified by two dimensional (2D) J -resolved spectroscopy. 19 F MAS spectra, 19 F↔ 23 Na and 19 F↔ 31 P rotational echo double resonance (REDOR) prove that F − ions are involved into the glass networks through Y-F•••Na and P-F•••Na linkages. The 31 P { 19 F} J -coupling based heteronuclear multiple quantum coherence ( J -HMQC) spectrum proves that F − ions selectively connect with Q 1 species. F − ions show significant preference to connecting with Y 3+ over P 5+ .