Abstract
We have performed wide-time-range photon correlation spectroscopy (PCS) on poly(propylene glycol) to probe the dynamics in the glass transition range. In addition to the primary (α) relaxation which shows stretched-exponential behavior, we observe two relaxation processes not witnessed in PCS before. They are assigned to α’ and β processes and exhibit similar power-law decays. All three relaxations are analyzed in terms of recent mode-coupling theories and the inherent scaling relations are verified by independent determinations of the relevant exponents from the spectra.