The paper deals with the surface modification of the glass substrates using diffuse coplanar surface barrier discharge (DCSBD). The changes of surface properties after modification with plasma discharge were observed in time. During eight days, wetting angles were measured by the method of sessile drop, using distilled water and diiodomethane as testing liquids. The surface free energy and its polar and dispersion component were calculated using Fowkes method. The morphology and rms-roughness of modificated substrates were evaluated, using atomic force microscopy. The effect of modification by plasma discharge on the observed surface properties is the most noticeable immediately after modification. After 3 days, the observed surface properties of the modified surface are comparable to the unmodified surface.