A study of electrical conductance of hydrogenated amorphous silicon (a-Si:H) films deposited on optical waveguides in a soda-lime glass (SLG) substrate is carried out, from the viewpoint of electrical instability of a-Si:H caused by the penetration of Na ions from the glass into the film. The optical waveguides were prepared by K+–Na+ or Ag+–Na+ ion exchange using thermal or field-assisted methods. The effective thickness of optical waveguides was of several micrometers. The obtained results show that in the case of a-Si:H film deposited on silver waveguide there is a dependence of electrical conductance on measurement duration, if strongly weakened as compared with film deposited on the original SLG substrate. The a-Si:H films deposited on potassium waveguide and on Na-extracted surface are as stable, as the referent samples with Corning 7059 (Na-free) glass substrate.