I went to the NYC Police Museum today to verify that the article and accompanying text were genuine. They are, indeed.
Furthermore, there were a few shards of glass, with the following text, which I copied down:
Glass was a rare find at Ground Zero, where these shards were recovered. The collapse and fires pulverized and melted most of the glass from the Twin Towers 43,600 windows.
I find this 'explanation' unsettling. Before the collapse, most of the 43,600 windows were not melted by the fire. While huge hotspots developed, with the true cause not definitively known, in photos taken soon after collapse, we still don't see shards of glass on the topmost visible layer. So, melting of glass as an explanation makes no sense for this layer, either before or after the collapse.
So, we are left with "collapse" itself as an explanation, by which they mean impact and kinetic energy. By such reasoning, why do we not hear of plane impacts, or even high speed car impacts, "pulverizing" the glass of those vehicles? I know cars have special glass ("tempered", I think it's called) to prevent it from breaking into shards (it tends to crack, but still stay together, stuck to it's 'skin'), but since skyscraper windows can also fall out (hurricane, bad design + vibration), it makes sense to construct it similarly.
I suppose it might be a worthwhile design goal to make glass that pulverizes, though that's debatable since I don't think breathing in pulverized window glass dust is going to much healthier than breathing in fiberglass.