Description of the intermediate length scale structural motifs in sodium vanado-phosphate glasses by magnetic resonance spectroscopies

For the first time, the local and medium range orders in sodium vanado-phosphate glasses have been investigated by advanced magnetic resonance spectroscopy methods. One- and two-dimensional 31P/51V magic angle spinning nuclear magnetic resonance techniques (31P(51V) REAPDOR and 51V(31P) D-HMQC) have been used to monitor the formation of P-O-V5+ bonds and to provide the first accurate description of the intermediate length scale structural motifs in these glasses. The structural model has been completed by the investigation of the chemical environment of the V4+ ions (produced through the partial reduction of V5+ during the melting stage of the glass preparation) using standard continuous wave and advanced pulsed electron paramagnetic resonance techniques (HYSCORE). Finally, the combination of both sets of data leads to the first complete and precise structural model of the alkali vanado-phosphate glass system