Structural changes and elastic characteristics of permanently densified vitreous B2O3 (Articolo in rivista)

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  • Structural changes and elastic characteristics of permanently densified vitreous B2O3 (Articolo in rivista) (literal)
Anno
  • 2011-01-01T00:00:00+01:00 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#doi
  • 10.1103/PhysRevB.84.024207 (literal)
Alternative label
  • Giovanni Carini Jr., Edmondo Gilioli, Gaspare Tripodo, and Cirino Vasi (2011)
    Structural changes and elastic characteristics of permanently densified vitreous B2O3
    in Physical review. B, Condensed matter and materials physics (Online); APS, American physical society, College Park, MD (Stati Uniti d'America)
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • Giovanni Carini Jr., Edmondo Gilioli, Gaspare Tripodo, and Cirino Vasi (literal)
Pagina inizio
  • 024207-1 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#url
  • http://prb.aps.org/abstract/PRB/v84/i2/e024207 (literal)
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  • 84 (literal)
Rivista
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  • 7 (literal)
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  • 2 (literal)
Note
  • ISI Web of Science (WOS) (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
  • Univ Messina, Dipartimento Fis, I-98166 Messina, Italy; CNR, IMEM, Area Sci, I-43010 Parma, Italy; CNR, IPCF, Sez Messina, I-98166 Messina, Italy (literal)
Titolo
  • Structural changes and elastic characteristics of permanently densified vitreous B2O3 (literal)
Abstract
  • Inelastic light-scattering spectra of normal and permanently densified B2O3 glasses were investigated over the frequency range between 6 and 1600 cm-1. Densification from 1826 to 2320 kg/m3 was obtained by loading B2O3 glasses in a multianvil apparatus for synthesis at 2 and 4 GPa; they were fused at temperatures between 1400 and 1500 K and then were quenched at those pressures. It is shown that increasing densification gives rise to (i) a growing decrease of the intensity of the strong band at 808 cm-1, ascribed to the breathing vibration of boroxol rings, implying a reduction in the number of rings in the network and (ii) the appearance of a band at 775 cm-1 in the glass compacted at 4 GPa, which is assigned to the vibrations of structural units containing tetrahedral BO4 groups. The low-frequency Raman scattering includes the boson peak (BP), which dominates the spectra between 10 and 100 cm-1. Densification significantly decreases the intensity of the BP and shifts its position from about 26 cm-1, through 39 cm-1 (2-GPa glass), up to 68 cm-1 (4-GPa glass). These increases are stronger than those expected from the substantial hardening of the elastic continuum: The elastic moduli increase up to about a factor of 5 compared to those of normal glass. These observations imply that densification drives the system toward a structure having a more efficient packing of molecular units, causing substantial variations of the short- and medium-range orders with the formation of boron atoms in the four-fold-coordinated state at a quenching pressure of 4 GPa. (literal)
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