Volume relaxation of a-Se studied by mercury dilatometry

Mercury dilatometry was used to study volume relaxation of amorphous selenium (a-Se). Influence of experimental setting and reactivity of a-Se with mercury was studied using two differently constructed dilatometers (dissimilar sensitivity of sample volume change and dissimilar values of characteristic time constants of the dilatometers). Three types of volume–time–temperature experiments were made. Temperature of glass transition and thermal expansion coefficients in glassy and liquid state were determined from non-isothermal experiments. Volume relaxation was studied mainly on the basis of isothermal experiments. It was found that classical isothermal relaxation experiments are strongly influenced by the loss of information at the experiment beginning due to the proceeding relaxation. On the other hand, more complex thermal history experiments seem to be less dependent on these procedural parameters and were considered as most suitable for studying structural relaxation. The reaction of a-Se and mercury was found not to be influencing the results of volume relaxation measurements.