small tear in soft top window

[SoCalSun]

i've always dreaded the day when the plastic windows would either change color, crack or tear. i usually drive the '00 SL500 with the top down and only put it back up when i'm parking somewhere for any length of time. then, i look for covered parking to try and keep the soft top safe from the sun and from other elements bent on destroying it. (i haven't put the hard top on the car for over a year and the car is always garaged at home and at work).

i've had the sl now for 6 years and i can see slight tears starting from the edges of all 3 plastic windows. aside from the tears (all along the fold line/crease), the windows are in great condition. there are no discolorations and they don't look weathered at all. i think my undoing may have been my over use of the top up/down button in trying to protect the soft top. the longest tear is probably 1/2 inch right now, but to me, they look like they're getting slightly longer every time i put the top down/up.

my question is this...are there any products out there that i can use to weld/glue/keep-the-tear(s)-from-growing? or do i just have to grin and bear it and set aside some money for a future replacement of the plastic windows. btw, how much would that cost?

the canvas part of the soft top is in excellent condition so i hope i don't have to replace the entire top to fix the problem with the plastic windows. thanks in advance for your suggestions!

(sorry if this is a double post - it didn't seem to work the first time i clicked on 'submit')