  We present a high time resolution, multi-frequency linear polarization
analysis of Very Large Array (VLA) radio observations during some of the
brightest radio flaring (~1 Jy) activity of the 2015 outburst of V404 Cygni.
The VLA simultaneously captured the radio evolution in two bands (each with two
1 GHz base-bands), recorded at 5/7 GHz and 21/26 GHz, allowing for a broadband
polarimetric analysis. Given the source's high flux densities, we were able to
measure polarization on timescales of ~13 minutes, constituting one of the
highest temporal resolution radio polarimetric studies of a black hole X-ray
binary (BHXB) outburst to date. Across all base-bands, we detect variable,
weakly linearly polarized emission (<1%) with a single, bright peak in the
time-resolved polarization fraction, consistent with an origin in an evolving,
dynamic jet component. We applied two independent polarimetric methods to
extract the intrinsic electric vector position angles and rotation measures
from the 5 and 7 GHz base-band data and detected a variable intrinsic
polarization angle, indicative of a rapidly evolving local environment or a
complex magnetic field geometry. Comparisons to the simultaneous,
spatially-resolved observations taken with the Very Long Baseline Array at 15.6
GHz, do not show a significant connection between the jet ejections and the
polarization state.
