When you say "without a kiln", I assume you mean a standalone kiln, typically heated by a gas flame.  You can melt glass in a few minutes in a microwave using an inexpensive, lightweight microwave kiln.  You can buy them ready-made, like [this random example](https://www.amazon.com/Large-Microwave-Kiln-Glass-Fusing/dp/B012EV9LES) from Amazon (they're in the general range of $25-$40):

[![enter image description here][1]][1]

You can use them in your household microwave, or a dedicated cheap unit (stores like Walmart regularly have microwaves around $50 or less, and even an 800W unit will work).

You can make your own.  Here's an Instructable that covers one design very well: [DIY Microwave Kiln | Fuse Glass in Your Microwave](https://www.instructables.com/id/DIY-Microwave-Kiln-Fuse-Glass-in-Your-Microwave/).  The materials are available on Amazon if you can't find them locally.

  [1]: https://i.sstatic.net/xLVBp.png