No, they will not loose their functions of polarization effects.
The polarized lenses have a lminate that has the poarization effects in it sandwiched between two layers of lens. And never heard someone say that his polarized sunglasses loose polarization as time goes by. I only hear that transition lenses will loose their function of automatically adjust themselves in sun as the times goes by (usually about two years) Maybe you can try that to see if they will lose polarization effects or not.
No. if the sunglasses have the polarized lenses, they won't lose their polarize effects. If you think your sunglasses lose their polarization effects, you might have something else that is causing you to be more sensitive to the light, though. Higher elevation, medication changes, illness. Lots of things can affect your reaction to the sun. What's more, the polarized lenses will protect your eyes under the strong sunlight. But on the contrary, if you are under the dim light with polarized sunglasses, it will have a bad effect. At this time, the polarized sunglasses may hurt your vision.