A new form of near-field scanning optical microscopy (NSOM) for studying electric field induced dynamics in highly localized regions within birefringent thin film materials is presented. The method is applied to dynamics studies of polymer-dispersed liquid crystal (PDLC) films. A sinusoidally modulated voltage is applied between the NSOM probe and a conductive substrate, upon which the PDLC film is supported. A concentrated electric field is formed within the film, directly beneath the probe. Time-dependent molecular motion induced by this field is observed via crossed-polarized, transmitted-light near-field optical methods. It is shown that dynamics in volumes as small as 10^-15 cm³ may be probed using this method. Via lockin detection of the transmitted light intensity, amplitude and phase images of the local dynamics are recorded. Contrast in these images is utilized to better understand the local field induced reorientation process. Information on both the path through which the molecules reorient and spatial variations in the time scale for reorientation is obtained.