Strain point
From Fritipedia
This is the temperature at which the molecules in the glass stop flowing and moving. Below this point if the bead has not been annealed correctly these stresses will remain in the glass. (unless the glass is then subsequently annealed).
The strain point varies for each glass depending on the manufacturer, elements contained within the glass and the coefficiency of the glass
Effetre glass
The annealing range is between 493°C - 520°C and the strain point is 448°C
Bullseye
The ideal annealing temp is 504°C and strain point is 437°C