Sensitivity of High-Field Electron Paramagnetic Resonance to the reorientation of molecular guests in glassy polymers

Vasile Bercu (1) , Massimo Martinelli (1) , C A Massa (1) , Luca Pardi (1) , Dino Leporini (2)

1 IPCF - CNR Istituto per i Processi Chimico Fisici [Pisa]
2 University of Pisa - Università di Pisa

The reorientation of one paramagnetic molecule in glassy polystyrene is studied by High-Field Electron Paramagnetic Resonance spectroscopy at four different Larmor frequencies between 9.5 and 285 GHz. On increasing the Larmor frequency, the lineshape exhibits larger sensitivity to the rotational motion of the radical. Unfreezing the rotational dynamics by increasing the reorientation rate leads to considerable line shifts, whereas broadening effects are not dominant. The finding evidences that the paramagnetic molecule undergoes small-angle reorientation in the glassy matrix.

Mots clés: Physical Sciences

Vasile Bercu, Massimo Martinelli, C A Massa, Luca Pardi, Dino Leporini. Sensitivity of High-Field Electron Paramagnetic Resonance to the reorientation of molecular guests in glassy polymers. Philosophical Magazine, 2007, 87 (3-5), pp.795-798. ⟨10.1080/14786430601032378⟩. ⟨hal-00513793⟩