On the relation between positron annihilation lifetime spectroscopy and lattice‐hole‐theory free volume

• DOI: 10.1002/polb.20516
• Publication Date: 2005-07-07T22:20:48Z
• Authors: G. Consolati; F. Quasso; R. Simha; B. G. Olson
• Keywords: Molar mass; Positronium; Polystyrene; Volume fraction; Lattice (music)

Abstract A coincidence between the temperature‐dependent hole (free volume) fraction h above glass transition temperature, derived from lattice‐hole theory, and corresponding function Ps obtained positronium lifetime spectroscopy has been previously observed for four polystyrene fractions ranging 4000 to 400,000 in molar mass. This result was based on assumed proportionality of product orthopositronium intensity I 3 mean cavity volume, constant C being mass dependent. However, a recent analysis data volume arguments by Olson Jamieson revealed systematic departures two sets free functions. We reexamine situation departing customary assumption spherical cavities, allowing nonspherical geometries represented prismatic or cylindrical disks. Agreement spectroscopic thermodynamic functions ensues with fixed, temperature‐independent asymmetry factors decreasing increasing These tentative findings suggest that studies melts varying chain flexibility should be attempted. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Phys 43: 2225–2229,