Structural Studies of Fluoroborate Laser Glasses by Solid State NMR and EPR Spectroscopies

Abstract

The structure of glasses in the systems (100 – x)­B2O3–xPbF2 (x = 30, 40, and 50) and 50B2O3–(50 – x)­PbO–xPbF2 (x = 5, 10, 15, 20, 25, 30, 35, 40, and 45) has been studied by solid state NMR and EPR spectroscopies. On the basis of 11B and 19F high resolution solid state NMR as well as on 11B/19F double resonance results, we develop a quantitative structural description on the atomic scale. 19F NMR results indicate a systematic dependence of the fluoride speciation on PbF2 content: At low x-values, F– ions are predominantly found on BO3/2F– units, whereas, at higher x-values, fluoride tends to be sequestrated into amorphous domains rich in PbF2. In addition, both pulsed EPR studies of Yb3+ doped glasses and photophysical studies of Eu3+ doped samples indicate a mixed fluoride/borate coordination of the rare-earth ions and the absence of nanophase segregation effects.

Structural Studies of Rare Earth-Doped Fluoroborosilicate Glasses by Advanced Solid-State NMR

“…The site-selective REDOR dephasing curves are shown in part (b), obtained by systematically increasing the dipolar evolution time. The steep curvature observed in the initial part of the REDOR curve of F2 species indicates that B-bonded F species exist . However, the F1 signals exhibit a less dephasing effect owing to the remote dipolar interaction.…”

“…The F2 signal should be attributed to F−B linkages, as confirmed by 19 F{ 11 B} REDOR and 11 B{ 19 F} J-HMQC methods below. The Y-free glass was prepared to assist in the assignment of these 19 58 However, the F1 signals exhibit a less dephasing effect owing to the remote dipolar interaction. The accurate quantitative estimation of the B−F species is difficult because the remote-distance 11 B− 19 F interaction contributes a lot to the REDOR dephasing.…”

Effect of Li2O substitution on structures and properties of Nd3+‐doped Al(PO3)3‐Li2O glasses

“…Glass structure is hard to be comprehensively characterized due to the disorder arrangement of atoms and the low resolution of traditional techniques. The solid‐state nuclear magnetic resonance (SSNMR) technique is a powerful tool to characterize the hyperfine structure of glass materials . Pulse electron paramagnetic resonance (EPR) technique is an effective way to investigate the local environment of rare‐earth (RE) ions.…”

“…The solid-state nuclear magnetic resonance (SSNMR) technique is a powerful tool to characterize the hyperfine structure of glass materials. 15,16 Pulse electron paramagnetic resonance (EPR) technique is an effective way to investigate the local environment of rare-earth (RE) ions. Yu Yue et al 12 showed that the content of 31 P located in the second-order shell of Nd 3+ ions increased as P/Al ratio increased in Al 2 O 3 -P 2 O 5 -K 2 O glasses.…”

“…concentration on properties and structures of the 99.8[(1−x%)Al(PO 3 ) 3 −x%Li 2 O]-0.2Nd 2 O 3 glasses (mol%, x = 0,5,10,15,20) was systematically studied, and the structure-property relation was depicted.The SSNMR and Raman results suggest that there are mainly Q 2 species in 99.8Al(PO 3 ) 3 -0.2Nd 2 O 3 (mol%) glass. The addition of Li 2 O cannot change the connectivity between P and Al.…”