Experimental small-angle X-ray scattering investigation of initial stages of the spinodal decomposition in model sodium silicate glasses

摘要

The kinetics of the initial stages of the spinodal decomposition in model glasses of the Na_2O-SiO_2 system has been investigated in situ. It has been demonstrated that there is a quantitative agreement of the experimental results obtained in the framework of the Stephenson theory with the basic principles of modern theories and the data on direct determination of the viscosity, mobility, and diffusion. It has been found that the spatial-temporal evolution of the heterogeneous structure has a multistage character during spinodal decomposition. The characteristic size of the phase regions at each stage varies with time according to the power law. The sequence of stages and the values of exponents for the spinodal decomposition are as follows: 1/20, 1/4, 1/2, and 1/3.