Thermoluminescence in squalane

Squalane (hexamethyl tetracosane) freezes to a rigid amorphous glass. Phosphorescence measurements show two transitions at 110 and 147 K while thermoluminescence following γ radiolysis at 77 K gives a glow curve consisting of four distinct peaks, one of which can be associated with the presence of molecular oxygen in the sample. The three remaining peaks coincide with the two-phase transitions mentioned above and the melting point. Dose kinetics show the existence of two types of traps and lead to a simple model for the thermoluminescence mechanism. A tentative identification of the luminescence centres is made.