Is there any way to make the BCC Particle System particles freeze in space after x number of frames, stay frozen in space for x more number of frames and then continue to expand/decay? I have tried the Animation-TimeScale but that just causes the particles to implode on themselves when you decrease the value after having it set to say 100 (If I start the Animation-TimeScale at 100, set a key frame advance x number of frames set another key frame advance x number more key frames and set the value to 10, the particles expand in the beginning, then start imploding when the Animation-TimeScale starts decreasing from 100 to 10. Once the timeline hits the '10' key frame, the particles slowly start expanding again after they imploded on themselves.) I know I am probably missing something here.
One thing that you must do is enable the "manual animation" switch, which is a couple of parameters above the "time scale" parameter that you have been working with, then you will be able to control the speed of the particles to complete the effect that you are trying to achieve. Also, don't forget to set a "hold" keyframe for the "time scale" parameter so that the particle generation holds still within the frames that you want the stop motion to occur on and then resumes generation after it finds the second hold-linear keyframe for this parameter. If any of this seems unclear let me know and I'll write out the keyframes that demonstrate this more fully.
Thanks for the info Peter. Your suggestion worked exactly like I needed. It took me a few moments to figure it out, but once I did, I started understanding the functionality and expanded it beyond my original concept.