The described study concentrated on the investigation of II-VI semiconductor quantum dots, prepared as colloidal species imbedded in phosphate glass, or chemically deposited on a substrate. The ultimate goal of the present research was concerned with the examination of the influence of the surface/interface quality on the optical properties of those quantum dots. This was examined by the utilization of optically detected magnetic resonance spectroscopy. This method reflected knowledge of the chemical identity of the surface/interface trapping site, and trapped electron and trapped hole recombination mechanism. It also distinguished between radiative and nonradiative processes, determined the spin-lattice relaxation, estimated the trapped electron-hole exchange mechanism and the distribution pf defects at the surface.