Good suggestions. As was expected (grin).
One of the reasons that the chemical material made with pyro is a bit blurry etc is because I wanted to give the glass a bit of an age, so I added some roughness to it. When I take that away, the glass looks too plastic, so I have to restart tweaking the material.

I can also set the particles to a lesser emmission state so there is less "material" inside the beaker which would show more of the glass...

Pyro is not that difficult, really. As with most things you have to specify WHAT has to be done, and WHERE you want the effect. The Pyrocluster material defines what, and the Volume Tracer where. Most often, the Volume Tracer is placed on an Environment object because the smoke or whatever has to be seen in the environment of the scene. Yet you can also place it, like I did on any shape to confine it to that shape. The Pyro Material itself is added to an emitter of particles. It also allows preview. Here it is best to experiment with every setting. Then, because Pyro is a time-based renderer of smoke etc, you have to drag the timeline tab and try out with very small renders (saves time). To get pyro into a bottle like I did, you have to place the object to which you linked the Volume Tracer, here a sphere inside the bottle-with-a-glass-material and make it smaller. The reflection of the glass makes the pyro material reflect on the edges, so you do lose the thickness of the beaker.

As for the thickness of the glass: I will redraw the beaker with a spline (or a vector in Xara-hehee much easier- to control and export as AI) and rotate that around a spline.

This beaker was made, as an experiment, from a sphere from which I flattened the bottom (give points the same Y value) and extruded the top. Just trying out whether this method offers more options than spline-nurbsing.

Then I could add shadow, radiosity...but then I might have to let my poor "old" (???) PIII800 render for at least 24 hours I suppose, as Pyro itself is also very processor-intensive...

Thanks for the comment, and 'till soon.