Re: PCB Material
I guess, you are trying to choose a PCB material with a lower glass transition temperature. If you are doing so, then please keep in mind about the assembly temperatures to which your board would be subjected to. The lower the glass transition temperature, the more would be the chances of de-lamination and warpage and other assembly defects on the printed circuit board. Generally all the FR grade materials and CEM grade materials would be able to withstand a temperature of almost upto 250 degrees +.
I am not sure why you would want to compromise on the glass transition temperature parameter. Is it because of the application that demands to compromise on the cost and quality of the material?