Vitreous SiO2 was permanently densified at pressures ranging up to 8 GPa at 700 °C, where its density reached a value of 2.58 g/cm3. The series of glasses formed were analyzed by Raman spectroscopy and X-ray absorption near edge structure (XANES) spectroscopy at both the oxygen and silicon K-edges. Changes in the Raman spectra are most evident in the Si–O–Si bending and rocking region near 500 cm-1, as the broad band becomes narrower and shifts to higher frequency, indicating a narrower distribution of Si–O–Si bond angles in the compacted glasses. A pronounced shift to lower frequency of the weak high-frequency bands associated with Si–O stretching motions is also observed, indicating a lengthening of Si–O bonds with increasing densification. More subtle changes are observed in both the Si and O K-edge spectra, with the O K-edge appearing more sensitive to short-range structural modifications such as narrowing of the intertetrahedral angle. In contrast to the structure of permanently densified v-SiO2 formed at room temperature, in which medium-range order is mostly affected, densification at higher temperatures is accomplished at shorter range, although at the pressures of this study, the glass remains principally a fully polymerized tetrahedral framework glass.

Poe, B.t., Romano, C., Henderson, G. (2004). Raman and XANES spectroscopy of permanently densified vitreous silica. JOURNAL OF NON-CRYSTALLINE SOLIDS, 341(1-3), 162-169 [10.1016/j.jnoncrysol.2004.04.014].

Raman and XANES spectroscopy of permanently densified vitreous silica

ROMANO, Claudia;
2004-01-01

Abstract

Vitreous SiO2 was permanently densified at pressures ranging up to 8 GPa at 700 °C, where its density reached a value of 2.58 g/cm3. The series of glasses formed were analyzed by Raman spectroscopy and X-ray absorption near edge structure (XANES) spectroscopy at both the oxygen and silicon K-edges. Changes in the Raman spectra are most evident in the Si–O–Si bending and rocking region near 500 cm-1, as the broad band becomes narrower and shifts to higher frequency, indicating a narrower distribution of Si–O–Si bond angles in the compacted glasses. A pronounced shift to lower frequency of the weak high-frequency bands associated with Si–O stretching motions is also observed, indicating a lengthening of Si–O bonds with increasing densification. More subtle changes are observed in both the Si and O K-edge spectra, with the O K-edge appearing more sensitive to short-range structural modifications such as narrowing of the intertetrahedral angle. In contrast to the structure of permanently densified v-SiO2 formed at room temperature, in which medium-range order is mostly affected, densification at higher temperatures is accomplished at shorter range, although at the pressures of this study, the glass remains principally a fully polymerized tetrahedral framework glass.
2004
Poe, B.t., Romano, C., Henderson, G. (2004). Raman and XANES spectroscopy of permanently densified vitreous silica. JOURNAL OF NON-CRYSTALLINE SOLIDS, 341(1-3), 162-169 [10.1016/j.jnoncrysol.2004.04.014].
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11590/148483
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 63
  • ???jsp.display-item.citation.isi??? 59
social impact