Maybe - https://en.wikipedia.org/wiki/Roman_glass. I don't have enough chemistry context to say that the things they could produce would be helfpul/hurtful/neutral to any kind of chemical analysis.

Surprisingly, yes.

The Romans were remarkably good at glassware. This was one of the things that caught me off-guard when visting museums dedicated to ancient Rome vs ancient Greece. You go from no glass at all to lots of glass. Of course, I would say "suddenly", but in reality that's something like 7 centuries.

In addition, there's no real limit to the development of glass technology. Silica and wood are abundant. Trial and error will get you a very long way. And pretty things generally sell for nice money so there is lots of incentive.

Glassblowing was invented in the first century BC in Syria.

In general no, I doubt it. Even though there have been breaks and setbacks caused by the fall of empires and rise of religions, in general our technological and scientific progress has been a steady constant from ancient times until today.