The folks at Open3DP continue to investigate ways to produce 3D glass printing, and they've been quite successful so far. A recent post shows their work, but as one can clearly see in their image, a problem is shrinkage during the post-printing firing phase. Yes, that's right - the image on the right shows the degree of shrinkage by firing the original glass-printed object on the left.
This poses an interesting dilemma for future software makers: they'll have to include features that account for post-printing shrinkage. In the shrunken-head example above there's not much issue, but one can imagine the complexities that might occur with supports, tightly-fitting designs, multi-part assembly and designs dependent on precise dimensions.