  We report early optical linear polarization observations of two gamma-ray
bursts made with the MASTER robotic telescope network. We found the minimum
polar- ization for GRB150301B to be 8% at the beginning of the initial stage,
whereas we detected no polarization for GRB150413A either at the rising branch
or after the burst reached the power-law afterglow stage. This is the earliest
measurement of the polarization (in cosmological rest frame) of gamma-ray
bursts. The primary intent of the paper is to discover optical emission and
publish extremely rare (unique) high- quality light curves of the prompt
optical emission of gamma-ray bursts during the non-monotonic stage of their
evolution. We report that our team has discovered the optical counterpart of
one of the bursts, GRB150413A.
