Ortho-Positronium Annihilation and the Glass Transition of Nylon 6

Abstract
The mean life τ2 or ortho‐positronium annihilating in samples of Nylon 6 both dried and containing 0.5% of H2O has been measured as a function of temperature from 15°C up to 100°C. A sudden change of τ2 in the lifetime‐vs‐temperature curve was found at the glass‐transition temperature. The main glass transition for the dry sample is determined to be 50°C and for the sample containing water, 33°C. The Tg measured by this method is lower than that measured by other methods. This agrees well with the result for polystyrene observed by Stevens and Mao.