Using muon spin relaxation and ALC resonance spectroscopy the electron spin relaxation and mobility of the polymer P3HS will be measured as a function of temperature. The objectives are to determine whether the electron spin relaxation rate increases for P3HS compared to P3HT (already measured), so following the same trend as small molecules. Also to determine the temperature region where the ALC resonance disappears and compare it to the P3HT data, to see if the mass of the central atom (S or Se) on the chain influences this quenching of the ALC resonance.