Insertion of MoO3 in Borophosphate Glasses Investigated by Magnetic Resonance Spectroscopies

Abstract

Insertion of MoO3 oxide in the mixed borophosphate glass network has been analysed for the first time by advanced magnetic resonance spectroscopies. In a first time, the xMoO3-(100-x)(50PbO-10B2O3-40P2O5) composition line has been investigated by 1D (11B, 31P, 95Mo) and 2D-correlation NMR (11B DQ-SQ, 11B(31P) D-HMQC) at high magnetic field (18.8 T). The set of data allowed analyzing both local and medium range orders and identifying the modifications in the BOB and /or BOP mixing induced by the MoO3 insertion. In a second step, continuous wave EPR has been used to detect the presence of Mo5+ ions, resulting from partial reduction of Mo6+ during the melting stage and the chemical environment around Mo5+ species has been documented for the first time by pulsed EPR technique (HYSCORE). Altogether, the data contribute to a better understanding of the glass network modifications induced by the MoO3 insertion, including the non-linear evolution of the glass transition temperature that has been explained by a modification of the glass network nature.