Google's support pages have been updated, providing information about the functions available in Glass. The setup guide states that users wishing to log into their Google account on Glass via an Android phone will have to scan a QR code displayed on the phone's screen., rather than making use of NFC. This also occurs when a user wishes to start a screencast from Glass.
There are a number of possible reasons for the omission of NFC in the current version of Glass ,with space constraints being perhaps the most likely candidate. However, it's also possible that Google see pairing via the camera as providing a superior user experience when compared to having to raise a phone or tablet to eye level.
It should of course be reiterated that all current versions of Glass are pre-production units, meaning that it is still possible that retail versions of the device will feature NFC hardware.
Follow NFC Brief on Twitter to stay informed about the latest in NFC technology: