  We report the first systematic search for blazars among broad-absorption-line
(BAL) quasars. This is based on our intranight optical monitoring of a
well-defined sample of 10 candidates selected on the criteria of a flat
spectrum and an abnormally high linear polarization at radio wavelengths. A
small population of BAL blazars can be expected in the 'polar model' of BAL
quasars. However, no such case is found, since none of our 30 monitoring
sessions devoted to the 10 candidates yielded a positive detection of
intra-night optical variability (INOV), which is uncharacteristic of blazars.
This lack of INOV detection contrasts with the high duty cycle of INOV observed
for a comparison sample of 15 'normal' (i.e., non-BAL) blazars. Some possible
implications of this are pointed out.
