Question
After a period of time, my violets pull away at the top of soil.  It is as if the roots have rotted away.

Answer
Gloria, unless you can visually see the roots "rotting", then it sounds as if they are just pulling away. Lots of older violets do this. It is bothersome, but can be treated by repotting with lots of healthy soil, also by top-dressing, which is done by taking some healthy soil and incorporating it into the old soil. Then, take an instrument such as a simple kitchen fork and work the new soil gently into the old. Build it up around the large stem where it looks like the roots are separating. That should take care of it. Then observe that violet for moisture, light and possible blooms for several months. Don't do this if indeed you see rotting, though. The rotting usually means death of the roots due to too much moisture, or even worse - a fungal infection, in which case the plant would need to be destroyed, as fungal infections can be spread to other plants.