Q:

Temperature and flash corruption in microcontrollers

I'm repairing quite the pricey device, where a strain gauge failed. It's a pressurized device, and the strain gauge measures the internal pressure by means of it. The crux of the matter is that the strain gauge goes on a small metal cylinder epoxied to the PCB itself.
To install a new one, I will need to use hot curing resin, but I want to avoid having to remove the metal cylinder to reduce risks of damage and potential surprises. This means baking the whole PCB, MCU included, which worries me a lot since I have no clue whether it could become corrupted and I can't reprogram it.
I have 3 options for hot curing with Adhesive A:

1 hour at 190 °C
3 hours at 170 °C
6 hours at 160 °C

And other 3 with Adhesive B:

30 minutes at 200 °C
1 hour a 180 °C
3 hours  a 150 °C.

Now, the max storage temperature I saw in the datasheets of some ICs on the board is 125 °C which is what is deterring me from attempting this.
I found this question that basically asks the same, but I'm looking for a more formal resource if anyone has one.
I'm also thinking if there's a possibility of insulating the rest of the PCB since the topology allows it.
Thank you very much in advance.

A:

A rough back of the envelope calculation indicates that a device with a minimum 20 year retention at 110’C would last about 1/256 of that time at 190’C so you’d be knocking off a year or two from the life. 200’C is a wash with the halving for 10’C approximation so I would pick the lower temperature I think. An hour at 190’C is much worse than a few seconds at reflow temperature when it comes to retention. At 230’C, 30 seconds is the equivalent of only 4 minutes at 190’C.  
Of course my estimate using that rule of thumb may be completely worthless— perhaps you could procure a sample of the MCU chip, program it, bake it for (say) 10 and then 20 hours and see if it loses bits. 
Or find some way to selectively cool the MCU chip. 

