%0 Conference Paper
%F Oral 
%T RING DENSITY AND INTER-TETRAHEDRA BOND ANGLE OF SILICATE GLASSES: A FEMTOSECOND AND RAMAN SPECTROSCOPY STUDY
%+ Laboratoire des colloïdes, verres et nanomatériaux (LCVN)
%+ Centre de physique moléculaire optique et hertzienne (CPMOH)
%+ Laboratoire de Spectrométrie Ionique et Moléculaire (LASIM)
%A Hehlen, Bernard
%A Noguera, Olivier
%A Langot, P.
%A Vallée, F.
%< avec comité de lecture
%Z LCVN:10-061
%B NCM - 11th International Conference on the Structure of Non-Crystalline Materials
%C Paris, France
%8 2010-06-27
%D 2010
%Z Physics [physics]/Condensed Matter [cond-mat]/Disordered Systems and Neural Networks [cond-mat.dis-nn]Conference papers
%X The concentration of the fourfold and threefold ring modes of normal and densified silica has been quantitatively extracted using time-domain Raman spectroscopy. Their frequency and width are precisely determined even when they are partly masked by a broad background in spontaneous Raman spectroscopy [1,2]. Experiments performed in GeO2 also reveal the existence of a weak vibrational mode ascribed to oxygen motion in three-membered rings [3]. In permanently densified silicas, the variation of the Raman intensity upon densification is very different for bending and stretching modes. For the former we find a Raman coupling-to-light coefficient CB µ w2. This allows to derive a simple law relating the frequency of the bending modes with the Si-O-Si bond-angle in the network and in the fourfold and threefold rings [4]. The model has been applied to densified silicas and sodo-silicates glasses, and the results compare well to numerical simulations. This simple Raman-spectra analysis could become part of the routine characterization of the local and medium range structure of silica-based glasses.
%G English
%L hal-00528016
%U https://hal.science/hal-00528016
%~ CNRS
%~ UNIV-LYON1
%~ UNIV-MONTP2
%~ LCVN
%~ PRUNEL
%~ LOMA
%~ UNIV-MONTPELLIER
%~ UDL
%~ UNIV-LYON
%~ UM1-UM2