Publications

Authors:

Cassetta, M.; Sorarù, G. D.; Callone, E.; Dirè, S.; Abebe, A. M.; Mariazzi, S.; Brusa, R. S.; Giarola, M.; Daldosso, N.; Biesuz, M.

Title:

From SiO1.5CH3 to vitreous SiO2: A structural evolution study

Year:

2025

Type of item:

Articolo in Rivista

Tipologia ANVUR:

Articolo su rivista

Language:

Inglese

Referee:

No

Name of journal:

Journal of Non-crystalline Solids

ISSN of journal:

0022-3093

N° Volume:

648

:

Elsevier Science

Page numbers:

123327-123335

Keyword:

Methyl-silsesquioxane; Vitrification; Silica glass

Short description of contents:

The conversion of SiO1.5CH3 into SiO2 glass by pyrolysis in air has been studied by combining density measurements, vibrational spectroscopy, positron annihilation spectroscopy, and nuclear magnetic resonance. The results show that a critical transition takes place between 400 and 500 degrees C and at 600 degrees C the organic features are completely removed. The conversion of the hybrid structure into a fully inorganic network takes place through the formation of metastable 3-membered rings that progressively evolve into more stable 5+ rings as the pyrolysis temperature increases. The evolution of the organic moieties is coupled with the formation of Si-OH and molecular water trapped in the network which are well visible between 500 and 800 degrees C. In such temperature regions, a clear evolution of the network density can be detected, though the amount of free volume is nearly constant (due to the presence of trapped H2O). Only at 1250 degrees C, the network is comparable with a melt-derived glass.

Product ID:

145038

Handle IRIS:

11562/1159607

Last Modified:

April 13, 2025

Bibliographic citation:

Cassetta, M.; Sorarù, G. D.; Callone, E.; Dirè, S.; Abebe, A. M.; Mariazzi, S.; Brusa, R. S.; Giarola, M.; Daldosso, N.; Biesuz, M., From SiO1.5CH3 to vitreous SiO2: A structural evolution study «Journal of Non-crystalline Solids» , vol. 648 , 2025 , pp. 123327-123335

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