The relative importance of factors affecting the low temperature ALC spectra of organic molecular systems such as polymers and small molecules is a topical issue. Polybutadiene is known from earlier PSI studies to show a remarkably strong temperature dependence in its muon generated radical spectra in the 200K-250K region. This proposal aims to study this behaviour in more detail, taking advantage of the favourable features of the new HiFi spectometer in terms of its stability, general form of background, wide range of field and temperature and availability of time domain spectra. With an improved data set it is hoped to be able to shed some light on the anomalous temperature dependence seen in the earlier data, with implications for the possible interpretation of the spectra of other molecular materials currently being actively studied using HiFi