Glass is non-porous, so there should be no chlorine smell after rinsing it out and letting it dry. If you have filled it up with fresh water and it still smells strongly of chlorine, then there is another issue.
You didn't say, but tap water often has chlorine and can sometimes have an excessive amount. I grew up on well water and when I went to college, the tap water was so heavily chlorinated that I became sick to my stomach and had to buy bottled water from then on.
Also, you didn't say if what was in the tank and if you treated it as well. I assume you did. Was anything porous and could it have absorbed chlorine that it's now releasing, like driftwood? Time spent in the chlorine is also a consideration. I would use bleach to clean the gravel and ornaments in my tank about once a year. The white gravel would get stained and there would be snails and stuff that just didn't want to come off on the ornaments. I'd fill a container with water and add a little bleach. I'd soak the ornaments for no more than 15min. I let them sit a few hours in there once and the color leached out of the plastic plants and the leaves started falling off at the joints. The rock won't decay, so you can leave it in for longer, but I'd then thoroughly rinse everything, let it air dry, rinse again, and dry once more before returning to the tank. I never had any issues.
So I'd suggest several things. One is to get a Rubbermaid container as a temporary holding tank for your turtles and use fresh and treated water. Making sure to give them a landing to get completely dry and out of the water as water turtles require this, and also a light so they can digest their food. Then completely drain the tank and rinse all items, drying thoroughly. After sitting in the air overnight, sniff each item individually and determine where the strong chlorine smell is coming from. The tank is nothing but glass, and silicone, so no smell should be coming from there. I imagine it's an insert.
Once you identify the chlorine culprit, try to clean it as best as possible and consider replacing it if you can still smell it. You may also be able to save it by sitting it in a water bucket for a month or so, changing the water every few days. I know that backdrops made out of concrete leach toxins out this way.
Turtles don't really need the water to cycle, like fish do, but you'll need to cycle it for any feeder fish or fish you keep in with the turtles for show. You need a filter as turtles dirty water extremely quickly and the toxins are good for them and are lethal to the fish.
I think this should solve your issue. It's good to treat chlorinated water, but it's would be very beneficial for you to have a Rubbermaid container somewhere, such as your garage, where you can let the water sit and dechlorinate. If you have well water, then this isn't an issue for you. I hope these steps can help you get your tank back on tract.