Dielectric Measurement and Analysis of Ultrastable PMMA Glass

Abstract

A stable glass, distinguished from an ordinary glass, has phenomenal characteristics such as a high density and a high kinetic stability. In this project, stable glasses of poly(methyl methacrylate) (PMMA) are produced by physical vapor deposition (PVD), and the dielectric responses of the vapor-deposited PMMA glasses are measured at 1 kHz with a high precision capacitance bridge. Measurements of the dielectric loss and storage have been done by heating and cooling the vapor-deposited PMMA glasses, where the heating and cooling cycles are used to rejuvenate the vapor-deposited PMMA glasses and to directly compare stable and nominally rejuvenated glasses. A noticeable suppression in β relaxation peak could be observed in the dielectric loss curve for vapor-deposited glasses (stable glasses) as compared to that for rejuvenated glasses (ordinary glasses). This finding implies that the glass stability essentially influences the dielectric relaxation.