On the na + self-diffusion and electrical conductivity of Na 2O-B 2O 3-SiO 2 glasses derived from the Na 2O·2SiO 2 glass

Abstract

Five borosilicate glasses, whose composition is deduced from that of the disilicate glass (Na2O·2SiO2). are investigated for hydrolytic durability and for Na+ transport properties. The motion of the Na+ ions is studied by measurements of the 22Na tracer-diffusion coefficients D* and of the electrical conductivity σ in dependence on temperature. The deduced activation parameters (EA.D, D0: EA.σ, σ0) and the Haven ratio HR = D*/Dn are discussed in relation to Na+ concentration and to structural features of the glasses. The results are compared with the behaviour of binary sodium silicate glasses with related Na+ concentrations.