You can view the animatable properties of animation layers themselves (such as Weight) in the Time Slider, Graph Editor, or Dope Sheet.
To set up these animation editors to show the weight animation for a selected layer, do the following:
To view the layer’s Weight animation in the Time Slider
 -click
            the Time Slider and select Display
               Key Ticks > Show Layer Weight, if it is not already
            on.
-click
            the Time Slider and select Display
               Key Ticks > Show Layer Weight, if it is not already
            on. 
            The Weight keys for the animation layer display in the Time Slider.
To view the layer’s Weight animation in the Graph Editor
 -click
            the Outliner area and select Auto-expand layers if
            it is not already on.
-click
            the Outliner area and select Auto-expand layers if
            it is not already on.
          -click
            the Outliner area again and select Animation Layers Filter >
               Show Layer Weight if it is not already on.
-click
            the Outliner area again and select Animation Layers Filter >
               Show Layer Weight if it is not already on.
            
         To view the layer’s Weight animation in the Dope Sheet
 -click
            the Outliner area and select Animation Layers Filter
               > Show Layer Weight.
-click
            the Outliner area and select Animation Layers Filter
               > Show Layer Weight.