<div class="container">
  <button id="button"></button>
</div>
$green: #1ECD97;
$gray: #bbbbbb;
* {
  font-family: 'Roboto', sans-serif;
}
.container {
  position: absolute;
  top:50%;
  left:50%;
  margin-left: -65px;
  margin-top: -20px;
  width: 130px;
  height: 40px;
  text-align: center;
}
button {
  outline:none;
  height: 40px;
  text-align: center;
  width: 130px;
  border-radius:40px;
  background: #fff;
  border: 2px solid $green;
  color:$green;
  letter-spacing:1px;
  text-shadow:0;
  font:{
    size:12px;
    weight:bold;
  }
  cursor: pointer;
  transition: all 0.25s ease;
  &:hover {
    color:white;
    background: $green;
  }
  &:active {
    //letter-spacing: 2px;
    letter-spacing: 2px ;
  }
  &:after {
    content:"SUBMIT";
  }
}
.onclic {
  width: 40px;
  border-color:$gray;
  border-width:3px;
  font-size:0;
  border-left-color:$green;
  animation: rotating 2s 0.25s linear infinite;

  &:after {
    content:"";
  }
  &:hover {
    color:$green;
    background: white;
  }
}
.validate {
  font-size:13px;
  color: white;
  background: $green;
  &:after {
    font-family:'FontAwesome';
    content:"\f00c";
  }
}

@keyframes rotating {
  from {
    transform: rotate(0deg);
  }
  to {
    transform: rotate(360deg);
  }
}
View Compiled
$(function() {
  $( "#button" ).click(function() {
    $( "#button" ).addClass( "onclic", 250, validate);
  });

  function validate() {
    setTimeout(function() {
      $( "#button" ).removeClass( "onclic" );
      $( "#button" ).addClass( "validate", 450, callback );
    }, 2250 );
  }
    function callback() {
      setTimeout(function() {
        $( "#button" ).removeClass( "validate" );
      }, 1250 );
    }
  });

External CSS

  1. https://ajax.googleapis.com/ajax/libs/jqueryui/1.11.2/themes/smoothness/jquery-ui.css
  2. https://netdna.bootstrapcdn.com/font-awesome/4.0.3/css/font-awesome.css

External JavaScript

  1. https://cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js
  2. https://ajax.googleapis.com/ajax/libs/jqueryui/1.11.2/jquery-ui.min.js