In-situ structural analysis of silicate supercooled liquids through deep-UV Raman spectroscopy
- 1Department of Engineering for Innovation Medicine, University of Verona, I-37134 Verona, Italy
- 2Department of Industrial Engineering, University of Trento, I-38122 Trento, Italy
- 3Elettra Sincrotrone Trieste S.C.p.A., I-34149 Basovizza, Trieste, Italy
- 4Institut for Mineralogy, University of Hannover, D-30167 Hannover, Germany
- 5Department of Physical Sciences, Earth and Environment, University of Siena, I-53100 Siena, Italy
- 6Department of Earth Sciences, University of Torino, I-10125 Torino, Italy
The understanding of the vitrification processes encompasses all the fields between geo- and material- sciences. Glass represents a non-equilibrium picture of its parental super-cooled liquid (SCL) and the last melt fraction quenched after a volcanic eruption. The SCL is usually read as a system that moves away from equilibrium without having enough time to explore the phase-space. In these conditions it is unable to find new configurations, causing a drop of the thermodynamic equilibrium and a glass is formed. This system is named non-ergodic and at eruptive temperatures represent a key component that may experiences fragmentation [1]. This particular state is generally referred to the thermal interval preceding the glass transition temperature (Tg, T at which the viscosity is 1012 Pa s) and the monitoring of its micro-structural evolution requires the less invasive experimental technique. With this regard we have used the deep UV-Raman spectroscopy to investigate a set of silicate model-glasses, loaded with different iron contents. This spectroscopic approach allows for the acquisition of fluorescence-free spectra with a maximized signal in the high-wavenumber region (between 850-1300 cm-1) thus providing the finest conditions for the assessment of the tetrahedral arrangement through the Qn deconvolution analysis (n represents the number of bridging oxygens) [2]. Here we correlate the trend of each Qn unit with temperature across the Tg-interval. Our results display a clear T-dependent rearrangement of the Qn distribution in function of iron content. Our finding, supported by differential scanning calorimetry, thermal dilatometry, Mössbauer, FTIR and ATR measurements, may deliver helpful insights into the thermal-dependent microstructural evolution through the Tg-interval and the viscous behavior of silicate SCLs.
- [1] D. B. Dingwell, Science 273, 1054 (1996).
- [2] M. Cassetta, B. Rossi, S. Mazzocato, F. Vetere, G. Iezzi, A. Pisello, M. Zanatta, N. Daldosso, M. Giarola, and G. Mariotto, Chem. Geol. 644, 121867 (2024).
How to cite: Cassetta, M., D'Amico, F., Rossi, B., De Bona, E., Sambugaro, A., Biesuz, M., Almeev, R., Vetere, F., Giordano, D., Enrichi, F., Daldosso, N., and Mariotto, G.: In-situ structural analysis of silicate supercooled liquids through deep-UV Raman spectroscopy , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-12774, https://doi.org/10.5194/egusphere-egu24-12774, 2024.
