Electric Poling Behavior of Polymethylmethacrylate

The electrically stimulated acoustic wave method for observing resident space charge in dielectric insulators has been used to characterize the poling behavior of mm thickness samples of PMMA at temperatures from 40 to 90°C with moderate applied fields. Heterocharge appears in the bulk of every sample tested resulting in an apparent net increase of low frequency dielectric permittivity over time. In addition, a net internal charge was observed in some cases. This net charge was negative and located in the vicinity of the poling anode, and became most significant at 90°C.