Determination of non-homogeneity in Vycor glasses by means of positron annihilation and analysis of electron microscope Images

The paper presents results of measurements of heterogeneity of Vycor-type glasses, which contain pores. Concentrations and sizes of the pores affect glass quality and transmission of light. Lifetime parameters of positron annihilation in the samples have been measured. The same material was next investigated by means of electron microscopy to observe pores and measure their sizes. Comparison of the two measurements was then made; a correlation between the average lifetime for the long-life component, tau(2) (as obtained from the annihilation measurement), and average cavity radii (as obtained from the analysis of electron microscope images) was found. (C) 1999 Elsevier Science B.V. All rights reserved.