There is not an export/import option for the symbology that has been applied to a raster layer; therefore, the same symbology cannot be easily applied to other rasters. As a workaround, you can save the raster with the desired symbology to a Layer file using the Save As Layer File option. Use the Set Data Source button in the layer’s Properties Source tab to change the source for the Layer to a different raster dataset. The layer will then appear with the same symbology as the original. Repeat this process as necessary.