Question about bistable multivibrator op amps

[theBEAST]

Homework Statement

So for one of my labs, I had to make a bistable multivibrator and observe the transfer characteristics. The circuit is setup as follows:
http://i.imgur.com/1G4M7DE.jpg

(Image is too big to be inserted in this forum)

This resulted in the following hysteresis loop:
http://i.imgur.com/QfFGrzP.jpg

I noticed that in the graph, when the output flips from negative to positive (so looking at the vertical lines either on the left or right side), the voltage does not go straight up, instead it is slightly slanted. Does anyone know what could cause it to be slightly slanted?

Do note, that those vertical lines have been bolded by me on Paint.

Homework Equations

Vin_saturation = R1/R2 * L+

 

[CWatters]

Remember the scope plot is Vout vs Vin (eg not Vout vs time). How fast are you changing Vin? The transition time for Vout depends on the slew rate of the opamp and any load on it but let's say it takes a fixed time "t". In that time Vin is changing. The faster you change Vin the more those transitions will lean to the right. Try slowing down Vin and see what happens.