A study of time dependence of ortho-positronium annihilation in a poly(butadiene) at different temperatures: a meaning of I3 parameter

Positron annihilation measurements as a function of temperature and time have been carried out on a poly(butadiene). The measurements were performed at several temperature points from 14 to 225 K. The measurement time was several hours to four days. The analysis of data shows the following features: (I) the value of τ3 does not depend on the rate of cooling or time; (II) the value of I3 depends on the rate of cooling and the history of thermal treatment; (III) the dependence of I3 on time can be described by Debye function. But the rise in I3 is observed at very low temperatures; (IV) the I3 decays to value of I3 observed during very slow cooling.