Raman study of fractal voids in hot-pressed SiO2

The sensitivity of the dynamic (vibrational) properties of fractal nanocracks in hot-pressed silica to the thermal and mechanical prehistory of the material was studied by low-frequency Raman scattering. Samples were prepared from gel-derived and fused powdery products. The Raman data demonstrate the fractality of elementary continuity defects. From the frequency dependence of the Raman intensity, the values of the fracton (spectral) dimension that reflects the mid-range order in glass, and the dimensions of fractals in real space were calculated.