The effect of surface etching on second-harmonic (SH) intensity and Maker fringe pattern have been examined for poled borosilicate glasses containing CuCl. A drastic decrease in the SH intensity was observed with anode-side surface etching, while such a decrease did not appear when the cathode-side surface etching was carried out. However, after 20 mu m etching of the anode-side surface, a decrease in SH intensity with the cathode-side etching was observed. For some samples, the theoretical Maker fringe pattern derived on the assumption that the SH wave is generated from a thin layer near the anode-side surface is in good agreement with the experimental one. On the other hand, other samples show oscillation in the fringe, which originates from the interference of SH waves generated from both surfaces. These results suggest that the nonlinear layer is present at both surfaces, although it is much weaker near the cathode. It is thought that the origin of the nonlinearity is attributable to migration of Cu+ and Cl-. (C) 2000 American Institute of Physics. [S0021-8979(00)01218-4].