Time-resolved (in the microsecond time range) delayed luminescence spectra of several materials used in liquid-crystal displays and in the investigations of the Langmuir-Blodgett monolayers deposited on solid support are reported. Data enable one to distinguish between the luminescence of the sample and additional emission due to the windows material and/or to the conducting and orienting layers used as electrodes. All investigated support plates exhibit measurable delayed luminescence but in cases of quartz and pyrex plates, emission intensity was much lower than for sodium glass plates. The application of the orienting or conducting layers on the glass plates diminished the intensity of observed delayed luminescence of the support plates by shielding them against the excitation.