Internal friction in phosphoaluminate and borate glasses

Internal friction in sodium phosphoaluminate and borate glasses was investigated by torsion pendulum, beam vibration and pulse-echo methods. The Arrhenian relationship was verified in a frequency interval covering eight decades. A detailed analysis of the first peak was made to obtain the distribution of relaxation times and the distribution of activation entropy ΔS and activation enthalpy ΔH. The log-normal distributions were further compared to the Doremus theory and the observed discrepancy discussed.