No it is, kind of anyway, there's a whole argument about it. Some argue it's a solid, some argue it's a liquid, some say it's neither but somewhere in between. But, for example, really old glass windows will end up thicker at the bottom. It's basically a highly viscous liquid that takes an extremely long time to flow.

• https://www.scientificamerican.com/article/is-glass-really-a-liquid/
• https://www.scientificamerican.com/article/fact-fiction-glass-liquid/
• https://www.livescience.com/chemistry/is-glass-a-liquid-or-a-solid