We tried searching using the terms "operating temperature range" and FR-4, and found that we needed to specify that it was laminate we were looking for, in order to reduce the number of entries for components. However, the search for "FR-4 laminate" combined with "operating temperature" produced a dozen entries, most of which were consistent with the information given in Table 1. The dual rating, where electrical and mechanical top temperatures are different, is confirmed (for example) at http://www.tayloredindustries.com/nema_fr_4l.htm.
But even with a restricted search, it is clear that there are choices in glass transition temperature, and by implication of operating temperature range.
Using "epoxy-glass laminate" instead of FR-4 will yield more and different results, and generally a higher proportion of those results will be for materials that are evidently not the same as the ‘standard’ FR-4, which has an operating temperature in the range 130-140°C. Many of these will be associated with terms such as ‘multifunctional epoxy’ or ‘epoxy/PPO’, and different values for CTE.
The reason for these differences will become clearer as you move through this unit, but we hope we have made the point that saying ‘FR-4’ is rather like saying ‘Hoover’ instead of ‘vacuum cleaner’ – the principle may well be the same, but the specification and cost can vary substantially.