How to play a material's shader in an image? (Unity 5.2.0f3)

EDIT:

After posting my problem in another forum: https://gamedev.stackexchange.com/questions/163653/how-to-play-a-materials-shader-in-an-image-unity-5-2-0f3

We tried something else:

 IEnumerator WaitForInteractiveElementTransform(Animator animator)
 {
     if (animator != null)
     {
         while (animator.GetCurrentAnimatorStateInfo(0).length >
            animator.GetCurrentAnimatorStateInfo(0).normalizedTime)
         {
             yield return null;
         }
     }
     if (animatorBackground != null)
     {
         animatorBackground.SetBool("On", true);
     }
     else
     {
         P4.gameObject.SetActive(false);
         P4Fantasy.gameObject.SetActive(true);
     }
     state = SceneState.Unreal;
     StartCoroutine(SetMaterialFloatOverTime(spriteRendererMaterial, 1.5f, "Slider_Dissolve"));
 
 private IEnumerator SetMaterialFloatOverTime(Material material, float duration, string propertyName)
 {
     float timer = 0;
     while (timer < duration)
     {
         material.SetFloat(propertyName, timer);
         spriteRenderer.material = material;
         timer += Time.deltaTime;
         yield return null;
     }
  }

But unfortunately the same problem: We see the slider moving in the Unity inspector, but in-game the transition of the material isn't updating.

Here a topic we thought it would help: https://forum.unity.com/threads/material-isnt-updating-when-using-setfloat.530548/ Unfortunately nope. Here our shader:

 Shader "Shader Forge/SpriteDissolve" {
 Properties {
     _Slider_Dissolve ("Slider_Dissolve", Range(0, 1.5)) = 1.5
     _Slider_Border ("Slider_Border", Color) = (1,0.7655173,0,1)
     _Slider_Transition ("Slider_Transition", Range(0, 0.2)) = 0.1083302
     _0RED1GREEN2BLUE ("0 = RED // 1 = GREEN // 2= BLUE", Float ) = 0
     _Texture2 ("Texture 2", 2D) = "white" {}
     _Texture1 ("Texture 1", 2D) = "white" {}
     [MaterialToggle] PixelSnap ("Pixel snap", Float) = 0
 }
 SubShader {
     Tags {
         "IgnoreProjector"="True"
         "Queue"="Transparent"
         "RenderType"="Transparent"
         "CanUseSpriteAtlas"="True"
         "PreviewType"="Plane"
     }
 
     Blend SrcAlpha OneMinusSrcAlpha
 
     Pass {
         Name "FORWARD"
         Tags {
             "LightMode"="ForwardBase"
         }
 
         Blend One OneMinusSrcAlpha
         Cull Off
         ZWrite Off
 
         CGPROGRAM
         #pragma vertex vert
         #pragma fragment frag
         #define UNITY_PASS_FORWARDBASE
         #pragma multi_compile _ PIXELSNAP_ON
         #include "UnityCG.cginc"
         #pragma multi_compile_fwdbase
         #pragma exclude_renderers gles3 metal d3d11_9x xbox360 xboxone ps3 ps4 psp2 
         #pragma target 3.0
         uniform float _Slider_Dissolve;
         uniform float4 _Slider_Border;
         uniform float _Slider_Transition;
         uniform float _0RED1GREEN2BLUE;
         uniform sampler2D _Texture2; uniform float4 _Texture2_ST;
         uniform sampler2D _Texture1; uniform float4 _Texture1_ST;
         struct VertexInput {
             float4 vertex : POSITION;
             float2 texcoord0 : TEXCOORD0;
         };
         struct VertexOutput {
             float4 pos : SV_POSITION;
             float2 uv0 : TEXCOORD0;
         };
         VertexOutput vert (VertexInput v) {
             VertexOutput o = (VertexOutput)0;
             o.uv0 = v.texcoord0;
             o.pos = mul(UNITY_MATRIX_MVP, v.vertex );
             #ifdef PIXELSNAP_ON
                 o.pos = UnityPixelSnap(o.pos);
             #endif
             return o;
         }
         float4 frag(VertexOutput i, float facing : VFACE) : COLOR {
             float isFrontFace = ( facing >= 0 ? 1 : 0 );
             float faceSign = ( facing >= 0 ? 1 : -1 );
 ////// Lighting:
 ////// Emissive:
             float4 _Texture1_var = tex2D(_Texture1,TRANSFORM_TEX(i.uv0, _Texture1));
             float4 _Texture2_var = tex2D(_Texture2,TRANSFORM_TEX(i.uv0, _Texture2));
             float node_9964_if_leA = step(1.0,_0RED1GREEN2BLUE);
             float node_9964_if_leB = step(_0RED1GREEN2BLUE,1.0);
             float node_6089 = (lerp((node_9964_if_leA*_Texture1_var.b)+(node_9964_if_leB*_Texture1_var.r),_Texture1_var.g,node_9964_if_leA*node_9964_if_leB)*length((1.0 - i.uv0)));
             float node_2567 = step(node_6089,_Slider_Dissolve);
             float3 emissive = lerp(lerp(_Texture1_var.rgb,_Texture2_var.rgb,node_2567),_Slider_Border.rgb,(node_2567*step(_Slider_Dissolve,(node_6089+_Slider_Transition))*0.1));
             float3 finalColor = emissive;
             return fixed4(finalColor,1);
         }
         ENDCG
     }
 }
 FallBack "Diffuse"
 CustomEditor "ShaderForgeMaterialInspector"
 }

We hope someone can help us solve our problem Thanks!