  Banded spherulitic growth of crystal is observed in some materials with
spherically symmetric growth front and periodic radial variation of
birefringence. This variation of birefringence in quasi two dimensional
geometry produces concentric interference colour bands when viewed through
crossed polarisers. In most materials, the banded spherulites are found to be
formed by radially oriented periodically twisted fibrillar crystallites. Here,
we report the formation of banded spherulites due to the rhythmic growth of
concentric crystallite-rich and crystallite-poor bands for a pure compound
consisting of strongly polar rod like molecules. The compound exhibits
coexistence of untwisted fibrillar crystallites and an amorphous phase in its
most stable solid state. On sufficient supercooling of the sample from its
melting point, the banded spherulites are formed with a periodic variation of
composition of untwisted radially aligned fibrillar crystallites and an
amorphous solid phase. We have developed a time dependent Ginzburg-Landau model
to account for the observed banded spherulitic growth.
