Effects of polymorphism on positron lifetimes in tripalmitin

Abstract
Positron lifetime parameters have been measured in three polymorphic forms of tripalmitin. Differential scanning calorimetry and x‐ray powder diffractometry were used to identify the polymorphic forms. Each form exhibited a characteristic long lifetime τ2. Values of τ2 obtained at 22°C were 2.30, 1.44, and 2.23 nsec for the α, β, and β′ forms, respectively. Lifetime measurements as a function of temperature were also carried out for the α and β forms.