Electronic device enclosure with a glass member having an internal encoded marking

An electronic device, comprising:

• a housing;
• a display positioned at least partially within the housing;
• and
• a chemically strengthened glass member at least partially covering the display and defining:
• a first surface defining an exterior surface of the device and configured to receive touch inputs from a user;
• a second surface opposite the first surface;
• and
• an encoded marking within the chemically strengthened glass member and comprising:
• a group of marks, at least a subset of the marks in the group of marks positioned a first distance below the first surface of the chemically strengthened glass member and a second distance above the second surface of the chemically strengthened glass member and having a dimension between about 3 microns and about 10 microns.

A method of marking a glass member for an electronic device, comprising:

• laser forming, along an interior of the glass member, an encoded marking comprising a group of discrete marks each having a dimension between about 3 microns and about 10 microns;
• and
• after laser forming the encoded marking, chemically strengthening the glass member, comprising:
• placing the glass member in an ion exchange bath;
• and
• while the glass member is in the ion exchange bath, heating the glass member as a result of contact between the glass member and the ion exchange bath.