  Nearly all glass forming liquids display secondary relaxations, dynamical
modes seemingly distinct from the primary alpha relaxations. We show that
accounting for driving force fluctuations and the diversity of reconfiguring
shapes in the random first order transition theory yields a low free energy
tail on the activation barrier distribution which shares many of the features
ascribed to secondary relaxations. While primary relaxation takes place through
activated events involving compact regions, secondary relaxation corresponding
to the tail is governed by more ramified, string-like, or percolation-like
clusters of particles. These secondary relaxations merge with the primary
relaxation peak becoming dominant near the dynamical crossover temperature
$T_c$, where they smooth the transition between continuous dynamics described
by mode-coupling theory and activated events.
