Session D40 - Poster Session I.
POSTER session, Monday afternoon, March 12
Exhibit Hall, Washington State Convention Center
Using non-contact atomic force microscope techniques, we measure low frequency dielectric noise in a glassy polymer, polyvinyl-acetate (PVAc) near the glass transition (290K-310K) on a 50 nm length scale. Using a capacitance -measuring scheme ,with a PVAc film acting as the dielectric, we measured time dependent changes in dielectric polarization of the sample. The time series of PVAc polarization fluctuations, showed random telegraph switching (RTS) .We further observed that RTS has two to four states, associated with distinct molecular cluster configurations. By changing the applied electric field, we measured reproducible changes in RTS state occupancy probabilities, which was related to changes in cluster dipole moment in the z direction. We analyzed the RTS kinetics, by observing the RTS state occupancy time distribution. The distributions were fitted with a stretched exponential with 'bulk-like' stretching exponents.