A diffractive optical element is fabricated in soda-lime float glass using a simple and inexpensive process. The glass is sandwiched between a mesh anode (lattice constant 2 μm) and a flat metal cathode. Applying a direct current while at a moderately elevated temperature of 553 K induces thermal poling of the glass. The result is that the structured pattern of the electrode is imprinted on the glass as the electric field causes ion depleted regions where there is contact between the glass and electrode. The current-time dynamics of the structuring process along with X-ray element analysis and conductivity measurements are presented. Optical analyses of the resultant diffraction patterns of samples suggest that large- scale and complex patterns can be fabricated.