Industrial demand for high crystal growth rates in solid layer melt crystallization processes lead to liquid inclusions of impure melt in crystalline layers. An observed migration of the inclusions is induced by the temperature gradient which is always present when crystal layers are growing. Existing models to calculate the efficiency of separation by solid layer melt crystallization, however, do not consider the migration of the inclusions. The migration of liquid inclusions through organic layers (caprolactam/water) is investigated in a microscopic cell for different temperature gradients, sizes of inclusions, temperature levels and crystalline structures. The presented experimental results should serve in future as a basis for a mathematical description of the observed phenomena.