Structural properties of the range-II-and range-III order in amorphous-SiO 2 probed by electron paramagnetic resonance and Raman spectroscopy

In the present work we report an experimental investigation by electron paramagnetic resonance spectroscopy on the hyperfine structure of the E. point defect, probing the local arrangement of the network (range-II order), and by Raman spectroscopy on the D 1 and D 2 lines, probing mean features of the network (range-III order). Our studies, performed on a-SiO 2 samples thermally treated at 1000 °C in air for different time durations, show that changes of the hyperfine structure and of the D 1 and D 2 lines occur in a correlated way. These results give strong evidence that the range-II and range-III order properties are intimately related to each other and that these properties are determined by the history of the material. © 2010 EDP Sciences, Società Italiana di Fisica, Springer-Verlag