  We suggest a phenomenological theory of the polarization conversions effect,
an excitonic analog of the first-order spatial dispersion phenomena which is,
however, observed in the photoluminescence rather than in the passing light.
The optical polarization response of a model system of electrically neutral
quantum dots subject to the magnetic field along the growth axis was calculated
by means of the pseudospin method. All possible forms of the polarization
response are determined by nine different field-dependent coefficients which
represent, therefore, a natural basis for classification of a variety of
conversions. Existing experimental data can be well inscribed in this
classification scheme. Predictions were made regarding two effects which have
not been addressed experimentally.
