Linear-Limit Aging Times of Three Monoalcohols

Abstract

This paper presents data on the physical aging of three monoalcohols, 2-ethyl-1-butanol, 5-methyl-2-hexanol, and 1-phenyl-1-propanol. Aging is studied by monitoring the dielectric loss at a fixed frequency in the kHz range following temperature jumps of a few Kelvin’s magnitude, starting from states of equilibrium. The three alcohols differ in Debye relaxation strength and how much the Debye process is separated from the α process. We first demonstrate that single-parameter aging describes all data well and proceed to utilize this fact to identify the linear-limit normalized aging relaxation functions. From the Laplace transform of these functions, the linear-limit aging loss-peak angular frequency defines the inverse of the linear aging relaxation time. This allows for a comparison to the temperature dependence of the Debye and α dielectric relaxation times of the three monoalcohols. We conclude that the aging response for 5-methyl-2-hexanol and 2-ethyl-1-butanol follows the α relaxation, not the Debye process; no firm conclusion can be reached for 1-phenyl-1-propanol because its Debye and α processes are too close to be reliably distinguished.