Dielectric beta relaxations in the glassy state of salol?

The recently observed possibility to suppress the β-relaxation intensity of o-terphenyl by annealing at temperatures below the glass transition guided us to ask, whether the absence of a dielectric β process in many glass-forming materials, e.g., salol (phenyl salicylate), is a matter of the slow cooling rates usually employed to enter the glassy state. In order to assess this issue, we have quenched liquid salol to well below T_g at a rate of dT/dt = -490 K/min. Opposed to the case of cooling rates around -5 K/min or slower, this highly quenched sample displays a symmetric dielectric relaxation peak near f = 10³ Hz with an appreciable relaxation strength, Δ∈ = 6 × 10^-3. This novel feature of salol disappears irreversibly after a temperature excursion towards the glass transition at T_g = 220 K.