Glass transition of polydimethylsiloxane–vanadate hybrid materials studied through 17O and 51V NMR

Nuclear magnetic resonance (NMR) analysis of quadrupolar nuclei is shown to be a robust and powerful tool for studying glass transition of elastomeric nano-composites. In the case of polydimethylsiloxane–vanadate (PDMSV) materials, single pulses on 17O and 51V nuclei allow an observation of the effect on the quadrupolar splitting of motional changes above the calorimetric glass transition (177±1 K). Moreover, intensities of quadrupolar echoes are found sensitive to changes of motional correlation times occurring at the glass transition. Their variations give rise to consistent values of Tg (=184±5 K for 17O, =178±2 K for 51V). These results obtained through twin probing NMR analysis of half integer quadrupolar nuclei unambiguously confirm previous assumptions on chemical homogeneity and co-polymer effects.