This distinction depends not on the orientation of the molecules (parallel or perpendicular to the radial direction) but to the orientation of the major refractive index of the molecule relative to the radial vector. The spherulite polarity depends on the constituent molecules, but it can also change with temperature.
The distinction between parallel and perpendicular orientations of molecules is not relevant; instead, it's the alignment of the major refractive index with respect to the radial direction that matters. Spherulite polarity is determined by the molecular constituents, but it can change with thermal fluctuations.