The influence of an internal electric field generated in a sample on the value of the secondary electron emission coefficient and energy distributions of secondary electrons were studied. Microscopic glasses covered on both sides with thin conducting films were used as samples. The dependences of the secondary electron emission coefficient on the bias voltage of the sample for primary electron energies ranging from 25 eV to 200 eV were determined. The diagrams obtained are characterized by high non-monotonic behaviour. Some specific effects of the internal field, such as the presence of secondary electrons with energy greater than incident energy, were found.