We studied temporal degradation (aging) of liquid crystal (W) alignment on plasma beam processed substrates using, LC pretilt angle as a measure of this process. It was shown that aging may manifest itself either in pretilt angle decay or pretilt angle growth depending on LC and alignment material. The alteration. of electro-optic curves due to alignment aging was revealed. The weakest aging effect was observed for inorganic alignment layers obtained by PECVD method. An important reason of aging is chain scission and generation of low molecular weight reactive species disturbing surface anisotropy of atomic bonds and anisotropy of surface topology.