  We studied the microscopic polymer conformations in the droplet detachment
process of an elastic semi-dilute polyelectrolytic Xanthan solution by
measuring the instantaneous birefringence. As in earlier studies, we observe
the suppression of the finite time singularity of the pinch-off process and the
occurrence of an elastic filament. Our microscopic measurements reveal that the
relatively stiff Xanthan molecules are already significantly pre-stretched to
about 90 % of their final extension at the moment the filament appears. At
later stages of the detachment process, we find evidence of a concentration
enhancement due to the elongational flow.
