Effect of Bound Water on the Fractal Geometry of Nanosized Cracks in Glasses Prepared by Vacuum Pressure-Assisted Sintering
Pleiades Publishing Ltd - 2001
Tóm tắt
The vibrational properties of fractal nanocracks in vitreous SiO2samples prepared by vacuum pressure-assisted sintering are investigated by low-frequency Raman scattering spectroscopy. In the Raman spectrum, nanosized discontinuities with a fractal geometry manifest themselves in a specific frequency dependence of the scattering intensity: a monotonic decrease in the intensity according to the law of light scattering by acoustic vibrations localized on fractals is observed instead of the boson peak. The frequency dependence of the low-frequency Raman scattering intensity is analyzed for samples of different origins. A “smoothing” of the nanocrack profile with a decrease in the amount of bound water in the material is revealed.
Từ khóa
Tài liệu tham khảo
Petrovskii, G.T., Semenov, A.D., Smirnov, A.N., Shashkin, V.S., and Chmel', A.E., A Study on the Fractal Structure of Cracks in Vitreous SiO2 by Vibrational Spectroscopic Technique, Fiz. Khim. Stekla, 1999, vol. 25, no. 4, pp. 484-494 [Glass Phys. Chem. (Engl. transl.), 1999, vol. 25, no. 4, pp. 367-374].
Alexander, S. and Orbach, R., Density of States on Fractals: “Fracton, ” J. Phys. Lett., 1982, vol. 43, no. 17, pp. L625-L631.
Rammal, R. and Toulouse, G., Random Walks on Fractal Structures and Percolation Clusters, J. Phys. Lett., 1983, vol. 44, no. 1, pp. L13-L17.
Boukenter, A., Champagnon, B., Duval, E., and Rousset, J.L., Low-Frequency Raman Scattering from Disordered or Heterogeneous Materials, Philos. Mag. B, 1989, vol. 59, no. 1, pp. 125-131.
Alexander, S., Vibrations of Fractals and Scattering of Light from Aerogels, Phys. Rev. B: Condens. Matter, 1989, vol. 40, no. 11, pp. 7953-7965.
Ivanova, O.A., Petrovskii, G.T., Semenov, A.D., Smirnov, A.N., Ter-Nersesyants, V.E., Shashkin, V.S., and Chmel', A.E., The Structure of Sol-Gel Silica Subjected to Vitrification under Pressure, Steklo Keram., 1998, no. 4, pp. 3-6.
Dahmouche, K., Boukenter, A., Bovier, C., Dumas, J., Duval, E., and Serughetti, J., Raman Study of Gel-Glass Transformation in Base-Catalyzed Silica, J. Non-Cryst. Solids, 1992, vols. 147-148, no. 2, pp. 251-260.
Rousset, J.L., Duval, E., Boukenter, A., Champagnon, B., Monteil, A., and Serughetti, J., Gel-to-Glass Transformation of Silica, J. Non-Cryst. Solids, 1988, vol. 107, no. 1, pp. 27-34.
Mariotto, G., Montagna, M., Viliani, G., Campostrini, R., and Carturan, G., Low-Frequency Raman Scattering in Thermally Treated Silica Gels, J. Phys. C: Solid State Phys., 1988, vol. 21, pp. L797-L801.