We just painted the trim on our house a bright white which unfortunately now shows how yellowed our south facing windows have become and it looks terrible. Apparently, window companies will not replace this plastic/vinyl as it is part of the window seal and our only option is to replace the entire window, which we do not want or need to do. If we were to paint the vinyl th esame as our house trim, would it stick and for how long?
I’d ask manufacturer about painting your particular vinyl frames, however, it may not be a good idea. Exposed to elements, new paint may start peeling fast and it will make your house windows look very bad, they may have yellowish tint now but it is at least uniform.
You could also search online for suggestions and experiment on a piece of frame but, in general, vinyl isn’t the best base surface for painting.