Disclosed are various approaches to creating optical windows in glass covers. To create the glass cover with the optical window, a sheet of glass is reformed using a mold that includes a male portion having a first recess and a female portion having a second recess. The female portion of the mold mates with the male portion of the mold. The first recess is configured to form a first gas pocket and the second recess is configured to form a second gas pocket when the male and female portions of the mold are mated, where a cross sectional area of each of the first recess and the second recess is less than 15 square millimeters. A portion of the reformed glass corresponding to the optical window is positioned between the first gas pocket and the second gas pocket.