High throughput electro-thermal poling

A process for continuous electro-thermal poling a sheet or substrate of glass or glass ceramic material comprising a first surface and a second surface, the process comprising:

• heating the sheet or substrate to a temperature Te within a range of from 100° C. to Tg, where Tg is the glass transition temperature of the material of the sheet or substrate;
• feeding the sheet or substrate continuously or continually while applying a DC voltage bias VB within a range of from 100V to 10 kV, wherein the feeding and applying comprise physically and electrically contacting the first surface with at least one first roller that is one of an anode or a cathode electrically connected to a DC voltage source and contacting the second surface with the other of the anode or the cathode electrically connected to the DC voltage source;
• applying the DC voltage bias VB, whether constant or ramped or both, for a time Ti within a range of from 2 seconds to 30 minutes;
• and
• cooling the sheet or substrate to within 0-30° C. of ambient temperature.